Building new home, need help prepping for electric brewing

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Marc77

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I need some advice from the experienced people here. I'm guessing there's a thread for this on here but I've got a three year old laying across me trying to block me from seeing the computer, a one year old refusing to take a nap and a wife that's telling me to get ready to leave the house.

The foundation is already poured but none of the framing has started. So I know I can't put a drain in which...bummer. But I'd like to wire the basement for electric brewing. One of the breaker boxes is in the basement where I'll be brewing so running the 10/3 wire to a spot and putting in a dryer outlet won't be a problem. Would that be the best idea or would a spa panel be best? I'm still learning about electric brewing but need to learn faster then I have time so the construction doesn't get past where I can make changes.
 

mj1angier

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Well, don't rule out a drain yet...well maybe a floor drain, but you may be able to tie into one of the down stacks. Ok, I may be assuming that the drain are going from ground floor to basement to sewer...

I knew I would be brewing when we built our house, but thought I would be using propane. But I am am also a handy type and have a welder, so I had them put in a 100 amp sub box in my basement shop. Off of that is a 50 amp 240 plug for my welder. I had to match up the plug (3 prong) but it was a snap to go to all electric. Now if you don't weld, have them do the 4 prong plug. But also have a 20 amp 115 plug added close by for pumps, computers, radio, tv....
 

doug293cz

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Since you're building new, I'd recommend putting a 4-wire, 50A, GFCI protected circuit just for brewing. If you know where the brewing location will be, have them run the 50A circuit to that spot, and install a 4-prong outlet. You could go with just a 30A circuit, but that could be limiting in the future. The extra cost for the 50A circuit will just be rounding error in the total construction cost, and you can always run a 30A panel from the 50A outlet.

Brew on :mug:
 

bovine_OB

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Are you trying to decide between a spa panel and mounting a dryer outlet, or are you deciding between a spa panel and a GFCI breaker in the box downstairs? Certainly you need some sort of current protection when liquid and electricity are involved - thus the choice should be between the GFCI breaker and the spa panel. Each has its own pro's and con's.

GFCI breaker in panel -
pro's: neater, less exposed equipment
con's :roughly 2x as expensive depending on several factors, also it becomes a semi-permanent addition to your brewing location/house.

Spa panel -
pro's - portable (as in if you move again, you can lug this along with your brew gear), and most important to most folks - they are generally cheaper
con's - it becomes an extra box to be mounted

It all depends on the aesthetics of your brewing area and what kind of budget you are working with. Honestly, if I were to build a new house with a dedicated brew area, I'd just spend the money on a GFCI breaker in the panel, but as for my current setup I'm going with the spa panel so I can take my brew gear with me when we do eventually build our dream home.
 

lschiavo

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Rough in:

Water - convenient hlt fill, sink.
Drain - too late? Floor drain would have been awesome. Don't forget a sink.
Power - 50A imo
Ventilation - can be done after the fact but why?
Bling - not for me but now's your chance.

If I were starting from scratch, no way I'd bother with 30A.
 

SanPancho

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Foundation, framing, then rough plumbing. So while You cant get a drain under the slab you can still talk with plumber. They can tell you where they plan to run their vertical drops and then you can locate your brew area close to one of their runs. Get a restaurant prep table with sink and drainboard and you are all set. Then you can tell the electrician about where you want your panel.
 

SDBob

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+1 for the 100 amp panel. 50 amps is so borderline it's not worth it. 32 years in the trade.
 

SDBob

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Here's the math. Two 5500 watt elements, one in your HLT and one in your boil kettle, will draw 45.83 amps. That's a 60 amp circuit right there. Don't think for a minute there won't be times you'll want the ability to run them both at the same time. And a 100 amp sub will cost more than a 50, but not close to twice as much. It's a new house....
 
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Marc77

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I appreciate all the input! The basement won’t be finished so for right now it seems that outside of an in ground drain I’m not out too much and can research the rest.

I do like the idea of using 100 amp panels instead of 50 which I’ll have to see where that lands. Either way they can add them if they don’t already use 100’s. It’s just the pissing and moaning at this point. But like several have said, it’s a new house and the cost will be a drop in the bucket.
 

Mike_kever_kombi

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If you plan on using a 100 amp sub panel, you will need to make sure that you have 200 amp service line coming in to the house. Running 2 elements, pumps, computer/TV, Lights, exhaust fans, and everything else in your brew room will be pushing 60 total amps. If you only have 100 amp service coming in to the house, this will only leave you with 40 amps total for the rest of the house.

While a floor drain would be nice, it is not too late to add a wye to a sanitary stack. Make sure the Plumber sets it up for 2” pipe, not 1 1/2”, this way you can use 2 sinks (if needed).

Also have your HVAC contractor run a 6” exhaust duct to the area you plan on brewing at (near your newly roughed in drain).

You don’t necessarily need to finish everything out right now, but at least get everything thought out, and roughed in now. It will add minimal cost now, but save many headaches down the road.
 

doug293cz

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You shouldn't really need to put in a sub-panel, if your main panel has room for a 240V/50A and 2 x 120V/20A breakers for your brewery circuits.

Brew on :mug:
 

SDBob

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Lot's of benefits to having a sub-panel in the basement. So many in fact, I'd advise putting one there even if you weren't going to brew. Also lot's of benefits to having a floor drain (or drains) in an un-finished basement, again, whether you brew or not. Very easy to pipe floor drains to a sump, where a plug in sump pump with a float pumps it either outside or to the sewer if it's legal. This kind of infrastructure costs pennies on the dollar when building a new house vs. adding later. Just my opinion.
 

SDBob

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I'm also thinking how difficult it would be to brew if the nearest sink is upstairs...
 

doug293cz

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Lot's of benefits to having a sub-panel in the basement. So many in fact, I'd advise putting one there even if you weren't going to brew. ...
Can you elaborate please? In my previous home (the one that had a basement), the main panel was in the basement. What would be the benefits of having a sub-panel in the basement in that situation? If the main panel was in the garage on the main level, then I could see some benefits to a sub-panel in the basement.

Brew on :mug:
 

Dcpcooks

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You can still add a floor drain! Install an ejector pump and a pit.

I installed 2 240v 30 amp gfci breakers and 2 120 v 20 amp lines. Super flexible for any set up.

I highly suggest you install an 8” exhaust line and an 8” make up air line before you drywall. Way easier to install that before construction is completed.

Brewing inside on electric is the way to go. Especially in the winter in the northern states[emoji300]️[emoji300]️[emoji300]️[emoji300]️
 

itsnotrequired

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Can you elaborate please? In my previous home (the one that had a basement), the main panel was in the basement. What would be the benefits of having a sub-panel in the basement in that situation? If the main panel was in the garage on the main level, then I could see some benefits to a sub-panel in the basement.

Brew on :mug:
and that's the problem with some of these threads, assumptions are made on how the electrical system will be installed without knowing where panels are located, what size the service is, etc.

but you are correct, if the main panel is already in the basement, no real need for an additional subpanel down there.
 

SDBob

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and that's the problem with some of these threads, assumptions are made on how the electrical system will be installed without knowing where panels are located, what size the service is, etc.

but you are correct, if the main panel is already in the basement, no real need for an additional subpanel down there.
No question. Let me clarify why I advise a panel vs individual circuits. FLEXIBILITY. Future expansion, changes, ect. If your main panel is already in your basement there's obviously no need unless you run out of breaker space. If it's not, with a 100-amp circuit and a $50.00 panel you get flexibility downstream. You might want to weld down there someday, or add a burner element, who knows, who cares.

Talk to your electrician. Tell him/her what you want. You're doing the right thing here... casting a net to collect opinions and ideas before your design is literally cast in stone.
 

SDBob

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The foundation is already poured but none of the framing has started. So I know I can't put a drain in which...bummer.
You sure can. If you have a utility area where you can cut in a pit for a sump pump, some place you wouldn't mind an 18" x 18" metal grate on the floor. It's late but not too late. At least your discharge and electric for the pump can get inside a wall. Talk to your contractor. My gosh, you're going to wish you did when you start running the stairs every time you need a sink.
 

itsnotrequired

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No question. Let me clarify why I advise a panel vs individual circuits. FLEXIBILITY. Future expansion, changes, ect. If your main panel is already in your basement there's obviously no need unless you run out of breaker space. If it's not, with a 100-amp circuit and a $50.00 panel you get flexibility downstream. You might want to weld down there someday, or add a burner element, who knows, who cares.

Talk to your electrician. Tell him/her what you want. You're doing the right thing here... casting a net to collect opinions and ideas before your design is literally cast in stone.
i'm not the original owner of my home but when we moved in, there was a grand total of two spare positions in the main panel (no sub). it is in the basement and first major project was to finish it off. i debated swapping out some of the single pole breakers for tandems but decided a sub was much better (less rework of existing, ability to work in a completely dead panel, etc.) sub is physically adjacent to the main. it is a 100 amp panel with 16 spaces. at the time, i had no real plans for expansion but since the run was so short, i used a 100 amp breaker and #3 awg thhn conductors. seemed like overkill at the time but a cheap install.

fast-forward two years and i decide to build an electric sauna, very convenient to serve out of that sub. fast-forward another two years and i add an electric brewery, again using that sub. counting other miscellaneous circuits and now that sub is the panel with only two spare positions!;)
 

SDBob

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i'm not the original owner of my home but when we moved in, there was a grand total of two spare positions in the main panel (no sub). it is in the basement and first major project was to finish it off. i debated swapping out some of the single pole breakers for tandems but decided a sub was much better (less rework of existing, ability to work in a completely dead panel, etc.) sub is physically adjacent to the main. it is a 100 amp panel with 16 spaces. at the time, i had no real plans for expansion but since the run was so short, i used a 100 amp breaker and #3 awg thhn conductors. seemed like overkill at the time but a cheap install.

fast-forward two years and i decide to build an electric sauna, very convenient to serve out of that sub. fast-forward another two years and i add an electric brewery, again using that sub. counting other miscellaneous circuits and now that sub is the panel with only two spare positions!;)
THIS.
 

mirthfuldragon

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I need some advice from the experienced people here. I'm guessing there's a thread for this on here but I've got a three year old laying across me trying to block me from seeing the computer, a one year old refusing to take a nap and a wife that's telling me to get ready to leave the house.

The foundation is already poured but none of the framing has started. So I know I can't put a drain in which...bummer. But I'd like to wire the basement for electric brewing. One of the breaker boxes is in the basement where I'll be brewing so running the 10/3 wire to a spot and putting in a dryer outlet won't be a problem. Would that be the best idea or would a spa panel be best? I'm still learning about electric brewing but need to learn faster then I have time so the construction doesn't get past where I can make changes.
If you have the cash, talk to your electrician about running 400 amp service - as in two separate 200 amp panels. That amount of power is beyond overkill, but somebody once said that about 100 amp service. If you are starting from square one, it makes sense to future-proof. In the next two or three decades, electric cars are going to become a lot more common, so having the capability to run 50a or even 100a chargers are going to exist (Tesla's Twin Charger runs 80a!). Your electricial is probably going to look at you like you are nuts, but nobody has ever complained about too many breaker slots and too much amperage supply.
 

itsnotrequired

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If you have the cash, talk to your electrician about running 400 amp service - as in two separate 200 amp panels. That amount of power is beyond overkill, but somebody once said that about 100 amp service. If you are starting from square one, it makes sense to future-proof. In the next two or three decades, electric cars are going to become a lot more common, so having the capability to run 50a or even 100a chargers are going to exist (Tesla's Twin Charger runs 80a!). Your electricial is probably going to look at you like you are nuts, but nobody has ever complained about too many breaker slots and too much amperage supply.
the utility company may have a say in service size. you may be able to install 400 amp equipment in the home but they may only bring 200 amp worth of conductor to your home. or make you pay a premium for an 'oversized' service. the nec is pretty explicit about how to size a service. we don't even know the size of the op's home. typically, 400 amp services only apply to unusual situations or massive homes (e.g. 8000 sf and up).

not saying not to look into going to 400 amp, just a heads up there may be issues...
 

mj1angier

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If you have the cash, talk to your electrician about running 400 amp service - as in two separate 200 amp panels. That amount of power is beyond overkill, but somebody once said that about 100 amp service. If you are starting from square one, it makes sense to future-proof. In the next two or three decades, electric cars are going to become a lot more common, so having the capability to run 50a or even 100a chargers are going to exist (Tesla's Twin Charger runs 80a!). Your electricial is probably going to look at you like you are nuts, but nobody has ever complained about too many breaker slots and too much amperage supply.
This is what I have.
400 amp service in 2- 200 amp panels. One upstairs and one downstairs. Then a 100 amp sub-panel in my work shop/ brew room
 

SanPancho

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while a flood drain would be nice, it could be a bit of a mess to break up that slab. we're on a 15" matt slab with two layers of steel. you couldnt pay me to try and break that up.

but if your slab isnt "structural" and you can cut into it, then yeah, go for it. drop a sump, wire a pump, and enjoy. you can even build up some floor tile to slope down towards the sump if you're really messy about brewing.

but if you cant, then its really not a big deal to just do your brewing on a nice commercial table. it'll have a lip around all sides, so as to contain spills and run them down to the sink, and then right into your drain line. no biggie. not sure about where you are at but you can get them new for less than a grand, or used for half that or less. lots of out-of-the-way storage underneath the table, etc.

but yes, floor drain/sump would be great if your building codes will allow it without too much trouble.
 

lschiavo

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If you have the cash, talk to your electrician about running 400 amp service - as in two separate 200 amp panels. That amount of power is beyond overkill, but somebody once said that about 100 amp service. If you are starting from square one, it makes sense to future-proof. In the next two or three decades, electric cars are going to become a lot more common, so having the capability to run 50a or even 100a chargers are going to exist (Tesla's Twin Charger runs 80a!). Your electricial is probably going to look at you like you are nuts, but nobody has ever complained about too many breaker slots and too much amperage supply.
We are wiring a rather large house (11,000 sq-ft). We used a 320A meter pedestal (rated 400A peak) with (2) 200A main breakers to feed two separate 40-circuit 200A panels. Also needed (3) 30-circuit subpanels spread around the house. The pedestal is nice and is still considered a residential installation around here. I would consider that a lot of overkill on a smaller house though unless you have some serious electrical plans.
 
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Marc77

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This may be unpopular opinion, but I'd also add at least a half bath down there. :)
There will actually be a full bath down there. I've told SWMBO that I refuse to go up two floors to a bathroom any more (side to side split). So the bathroom will be one of the first additions to the new house.

Also, I actually got out and walked the lot to see the foundation and saw that the foundation and footings have been poured but the basement slab hasn't been poured. So I'm going to be asking for a drain to be placed where I'll be brewing. Also to have water installed there for a sink as well as an exhaust outlet to be put there.

The only thing I'm concerned about conveying is the size of the exhaust outlet. If I tell them a six inch exhaust hole for brewing I'm sure they'll have no idea what actually needs to be done...and to be fair, being so new to electric brewing, neither do I.
 
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SDBob

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I can't help but wonder how deep your sewer lateral must be to enable a basement bathroom. Septic maybe? 12' deep? Forgive me, I'm in California, I don't know of one house in my county with a basement. I lived in Cleveland 40 years ago and every house had a basement. Go figure... maybe leveraging square footage isn't a thing in CA, land is so cheap, right....?

{Edit: Just Googled it. Apparently a basement is almost a necessity in certain climates to get the foundation below the frost line. Learn something new everyday!}
 
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steveoatley

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for EASE.... have your brewery & bathroom - right next to each other

So they share the same water supply & drain

I did the same thing about 5 yrs ago

S

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2 vessel EHerms
 

itsnotrequired

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The only thing I'm concerned about conveying is the size of the exhaust outlet. If I tell them a six inch exhaust hole for brewing I'm sure they'll have no idea what actually needs to be done...and to be fair, being so new to electric brewing, neither do I.
just tell them it needs to accommodate a 6" round exhaust duct, they'll know how to size the opening. bathroom, dryer, whatever, the opening is all sized the same. no doubt they will ask what it is for, try explaining then. the exhaust opening should be in the rim joist.
 

ajdelange

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I'd definitely go with 400 Amp service and a subpanel for the brewing. Of course I'm saying this without knowing what else you are planning. There are detailed instructions on how to size the service (so many KVA per square foot, washer and dryer loads multiplied by a factor to account for the fact that they are not used all the time, so much for each motor etc) in the code but electric breweries aren't in there. Things like that and you wife's pottery kilns make the sizing difficult and it more or less comes down to what the electrician decides he should install based on what he thinks the inspector will allow and the utility will accept. It seems one can get a rough idea of required service by adding up all the breakers and dividing by 4 and I got my electrician to admit that this is pretty much what he does. If you have a dual pole breaker that counts as two breakers. Thus a two pole 50 amp breaker would add 100 phase amperes to the total implying an extra 25 amps demand on the service.

The utility may indeed weigh in Quebec Hydro made me install 600 amp service even though I explained over again that this was way overkill (OK, my French is non-existent) and I'm pretty sure they made me do this because I put a total of (3) 50 amp outlets in the garage and boat shed thinking I might install an electric brewing rig in one or the other of those locations. Using my rule of thumb those 3 outlets would impose 3*2*50/4 = 150 amps on service requirement. Suppose I have 50 breaker poles (not unreasonable in a medium sized modern house) averaging 25 A each (some are clearly bigger than 20 A) that would give 1250 phase amperes to which add the 600 phase amperes for the three 50 amp outlets and I'd have 1850 phase amperes. Divided by 4 that's 462.5 which is over 400 and the next service size is 600 so perhaps that's why they insisted on 600 amp service despite my pleadings that those outlets would only be used a tiny fraction of the time and that I am smart enough not to use them heavily when emergency electric heat is on. I guess the point is that the next guy who moves into that house may not be so smart.

Needless to say this cost me some $. New pole transformer, new feed wires and the service entrance equipment and switch gear (they made me put in a 600 amp transfer switch for my 200 amp generator!). So what did the actual loading turn out to be? The picture below shows it for the period starting December 1 and ending this morning (Jan 6). My 600 amp service has never had a demand of more than 140 amps imposed on it. Note that there was no brewing activity. Also note that is has been bloody cold in Quebec this December and, so far, in January. Had I decided to brew on the coldest day of the year (when the use of E heat was responsible for the peak demand), and used the full 50 amp capacity of one of those outlets, I would have had a peak load of 190 amps. That huge transfer switch, big transformer and load shedding equipment were totally unnecessary as I tried fruitlessly to explain to the electrician when he told me I needed all that stuff per Hydro Fiat.
OgdenElec.jpg

So I guess my advice would be to sit down with your electrician and ask him what size service he is planning and how he arrived at that number (you would expect it to be easier if you are both native speakers of the same language but that may non necessarily be the case). If he came up with a load that is less than 150 A (unlikely unless it's a pretty small house) then he would use 200 amp service and you can just tell him to install another 50 amp outlet (fed from a GFCI breaker) in an existing panel or sub panel. If the estimated load is greater than 200 A but less than 350 amp he will have specified 400 amp service and again you can install another 50 A circuit without trouble. The situation gets sticky if the has estimated the load at just a few amperes below 200 or 400 as and extra 50 amps would put you into the next bracket. If that's the case you would have to convince him that the derating factor for this outlet is small. A 20% factor would only add 5 amps to the service requirement and if he is at 390 Amps a 50 amp circuit with that derating factor would bring it to 395 and you'd still be under 400.

I'll also mention something I wish I had thought of. In shop, garage, brewery, basement etc. have the guy pull 12/3 to the outlet boxes rather than 12/2 and install receptacles that have the breakable links between the two outlets. This way you have 120 and 240 available at each outlet. You can use them as normal duplex outlets until such time as you might want to install a 240 volt outlet for a piece of shop equipment, for example or for temporary 240 you can make up an adpater cable with (2) 120V plugs on one end and a 240 V receptacle on the other.
 

lschiavo

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Wow AJ. You could start a factory in your house. I'm surprised you couldn't declare one 200A panel an emergency panel and put a non-service rated transfer switch on it's feeder. That's what we did in the house I mentioned above. Saves tons of money.

Your situation with electric heat is unheard of around here anymore. It does add a large load that must be accounted for though as you mentioned with your peak loading.

A lot depends on appliances. Gas cooking and dryers drop the load calculations a lot. I would recommend asking you electrician to do a calculation for you. It's quite simple actually. The worst part is gathering the information on appliances and things you probably don't even have yet.
 

ajdelange

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Wow AJ. You could start a factory in your house.
I was afraid that Hydro would report the installation to the RCMP as there are those in my area that engage in certain indoor agricultural practices during the long winter which consume a lot of electricity for grow lights.

I'm surprised you couldn't declare one 200A panel an emergency panel and put a non-service rated transfer switch on it's feeder. That's what we did in the house I mentioned above. Saves tons of money.
I tried something similar. I gave them instructions that the three 50 Amp outlets should be connected before the transfer switch so that their loads would never go through it but they kept insisting that Hydro said if there is a load on the property and a generator all the loads have to go through the transfer switch. That is, of course, ridiculous. They wired the three to the load side and used a contact on the switch to shed the three (and, BTW, my E-heat) whenever the generator runs though I had given instructions that the E-heat was to be staged when the generator came on. I even asked the general contractor if I should sue these guys and he made it clear that it would be nothing but a nightmare (or couche mar as they say up there). But yes, that transfer switch definitely belongs in a factory!


Your situation with electric heat is unheard of around here anymore. It does add a large load that must be accounted for though as you mentioned with your peak loading.
Note that the utility name is Quebec Hydro. Electricity is very cheap up there - about $0.08 kWh which in US $ is about $0.06. Use that to run a heat pump with a COP of nearly 4 and you've got cheap BTUs. Last month E-heat only ran 1.1 hrs. That cost me 1.1*15*0.06 = $0.99

A lot depends on appliances. Gas cooking and dryers drop the load calculations a lot. I would recommend asking you electrician to do a calculation for you. It's quite simple actually. The worst part is gathering the information on appliances and things you probably don't even have yet.
At this point you are clearly not addressing me any more but I will, nevertheless, comment. It may be well worth Marc77's time to get a copy of the code or a summary (www.buildersbook.com) and figure out how to do a load calculation himself. He will need to know about the number of circuits in the rooms, the square footage of the house washers, dryers etc.
 
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lschiavo

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Thats crazy. We run a restaurant, bar, and 15bbl brewery on 400amps service. Holy cow.
I know. I find many people severely overestimate their electrical service needs. It doesn't cost much to go from 100A to 200A so that's a no brainier on a new house. Going up from there gets costly quickly. That's why I mentioned the 11,000 sq-ft house (perspective). I believe the calculation came to about 280A. Hence the 320A service. That's a pretty big house and nowhere near needing a 400A service.
 
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ajdelange

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My house (in Va) is certainly much smaller than 11000 square feet and has 400A service. Am I way oversized? Over the last month the largest load I saw was 159 amps (this morning). The average load was 36.3 amps, and the median 35.2. The load was less than 100 amps 99.3% of the time. So ostensibly one might be tempted to say that I am oversized. But all I have to do is turn on the ovens, the dryer, set the thermostats up a bit and turn on some lights and I'm up to 200 amps. Clearly as there are lots of lights, space heaters, toasters, compressors, crockpots, dryers, saws, grinders... that I didn't turn on it's plain that I could exceed 200 amps by a fair margin but the evidence of the month's power consumption history makes it plain that for me to do so would be quite unlikely. I exceeded 150 A 0.015% of the time last month but keep in mind that as the total data collection period was 40,259 minutes that means more than 150 A was drawn for 6 minutes. So am I oversized? No. I'm just about right. As I can conceptually draw over 200 amps (even though doing so is so rare an event that I have not yet witnessed it it normal operation of the house) I need 400 amp service just as parts of my house had, per code, to be reinforced to withstand winds that I've never seen and most probably will not see in my lifetime.

The engineer in me says that the way to size a service is to collect data and size the service as the mean load plus some number of standard deviations. For the December data that number here is 18.6 which I am confident is plenty big enough. Were the service 200 amps n would be 8.2 which clearly is too small. Of course you can't do this when you are designing a house so the writers of the code have to do the next best thing which is to tally up all the loads and try to accommodate the fact that they are unlikely to be on at the same time through the use of load factors. So I think that though service sizing is very conservative it needs to be so. 18.6 sigmas sounds like an insane number but keep in mind that the distribution is far from Gaussian (skew 0.64, kurtosis 0.62).
 

lschiavo

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It is very enlightening when you can look at historical data. From what you have presented, you would never have tripped a 200A main. IMO, you should have a 200A service.

Sure, there is potential to overload with any service. What would be the penalty if an overload happened? ...reset the main breaker. It's such an unlikely event to overload with no real penalty. The almost negligible chance of an overload does not justify the extra cost of an oversized service IMO.
 
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ajdelange

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It is very enlightening when you can look at historical data. From what you have presented, you would never have tripped a 200A main.
In the normal operation of the house in the time period for which I have records I did not exceed 200 A. But it is also clear that on a cold night where the A/A heatpumps switch over to E-heat and both compressors in the W/W heat pump are running simultaneously 48% of the time if my wife has got something in the ovens, my son is doing laundry and I've left lights on in the brewery and garage, I'm going to go over 200 Amps.

IMO, you should have a 200A service.
The most important aspect of this discussion to me is that your opinion is not shared by the NFPA nor, consequently, the building inspector, my insurance company, or my electrician. Nor do I share it. Given that service comes in chunks of 200A it is clear that 400A service is right for me. Now when I installed a generator last spring the same question came up: how big should it be and how big should the transfer switch be. My electrician (a good one - he listens to his customers) looked at my panels stuffed with probably, at that time, around 2200 - 2300 (it's 2565 now) phase amps worth of breakers, divided by 4 and concluded I had 600 amp service. I showed him load data but he wasn't really convinced until I sent him a photo of the service entrance with two fat CT's labeled 400 in big letters. 600 would be overkill. To draw more than 600 amperes every breaker in the house would have to be loaded to near its label capacity. The highest load I have observed represents 12% loading per pole relative to the rated breaker size and a 400 amp load would represent 31%. That's plenty of margin for the way I use electricity.


Sure, there is potential to overload with any service. What would be the penalty if an overload happened? ...reset the main breaker.
In my case the penalty would be going out into the freezing cold to replace two of these puppies in the main disconnect.

IMG_0800.jpeg


A big PITA. If I'm not here it would mean my spouse sitting in the dark and cold until I got home. I'm getting old enough that I have to recognize that the time when I'm going away and not coming home is not so far off as it used to be. After that, it means my wife sitting in the dark and cold waiting for the electrician to come. BTW, if the main disconnect had breakers rather than fuses it would be the same. My wife would have no clue as to what to do.


It's such an unlikely event to overload with no real penalty. The almost negligible chance of an overload does not justify the extra cost of an oversized service IMO.
Well, that's your opinion. I just wouldn't be comfortable based on what I have installed in this house (not typical by any means) and what the data I've collected tell me with 200A service. I'd have no room for expansion. And the potential penalties are indeed greater than you seem to think. The mjor one you missed is that if I presented a 200 amp service for inspection after the work I did last spring I would have failed and would require rework to get up to 400A service. That would cost me a lot of bucks, no doubt.

But now on to the fun part. Can I use a month of data in which I didn't see load over 200 amps to predict how many minutes in a year I might see over 200 amps? We, sure I can but I can't say how good the prediction is until I have a year's worth of data. The way I did it is illustrated in the graph below. The solid red curve shows, on the left axis, the number of minutes in a year for which the load would be, based on the distribution of loads in December, above the load shown on the x-axis. The dotted curve is the Weibull distribution that best fits the December distribution.

Weibull.jpg


You can draw your own conclusions. You would probably argue that at one minute a year it is not significant and might even reason that a breaker might not trip under load exceeding its rating for a minute or less. I'd reply that yes, that may be true but years of engineering practice have taught me that when one is this close to the limit it is best to 'err' on the safe side. The peace of mind is well worth the money.
 

SanPancho

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I know. I find many people severely overestimate their electrical service needs. It doesn't cost much to go from 100A to 200A so that's a no brainier on a new house. Going up from there gets costly quickly. That's why I mentioned the 11,000 sq-ft house (perspective). I believe the calculation came to about 280A. Hence the 320A service. That's a pretty big house and nowhere near needing a 400A service.
But as noted above, sometimes the engineering requires it. I guess it just depends on your local utilities. Here in CA, we are all about conservation and efficiency so you gotta spend crazy amouts for energy code work. And then after that, being in an urban area, even when you show large demand you practically gotta beg the city to give you extra room for future growth. They are paranoid about folks using extra capacity for un permitted work down the line, so the locals wont approve 600 if the calcs show you could get by with 400, even if the utility approves it.
 
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