208wye system but i want to run 5500w elements

[SanPancho]

is anyone aware of a way to run the full 5500w power out of heating elements for someone with 208wye power supply? in the US i've only ever really heated with gas (domestic hot water, tankless, brewhouses, furnaces, etc) and so im not familiar at all with wiring up your typical heating element. googling elements, some seem like they have three prongs, some look like only two prong.

two prongs will only get me 208v as i understand my system. and a large drop in wattage, something like only 4100watts. but if i were to have a "regular" 240 wiring and a three prong element i used with two conductors and a neutral then i get 240v and the full 5500w of power- yes?

is that what the 3rd prong is for? or is that supposed to be for ground? i assumed you grounded the element housing, not the actual elements, but again, i have no experience with these and that's just a half assed guess.

this is for roughly 75gal boils, with two big 5500w ripple elements, so its kind of a big freakin deal if im gonna get the "full" 11kw or only like 8kw...

 

[grampamark]

A 208V, single phase, power supply implies that you‘re in a building with 240V, three-phase, electrical service (tapping two lugs in a three-phase panel gives you 208V). Since 208 is 86.7% of 240, and volts x amps = watts, a 50A, 208V circuit would give you 10,400W.

A circuit supplied by a double pole breaker (one which connects to both hot legs of a service panel) doesn’t utilize a neutral. The third conductor is a ground.

 

[SanPancho]

sorry grampamark, but no. first off, 208 is not going to give you 86.7% of the power of 240v. its about 75%. voltage ratio squared times resistance. (example heating element )

secondly, we are in a building with 208 wye three phase. not 240v delta. you're confusing the single and 3 phase systems of each.

wye-powered single phase is 120v with a single hot and can be EITHER 208V ---OR 240V ---depending on how you wire it. 208 comes with two conductors but NO neutral. or you can get 240v in SINGLE phase by letting two hots run with a neutral because H1 to N is 120, and H2 to N is 120. but without the N leg the system gives you 208v because two legs of a 3phase are 208, and that's what is supplying the building.

hence my question about whether i could find a 3 blade element, use two hots AND the neutral to get 240v. otherwise, with only two hot legs and no neutral i get only 208V. and as seen above, thats only 4125watts. 8250 total. alot less than the 11k from having the full 240v powering the elements.

 

[grampamark]

I love it when someone asks a question and then argues with the answer.

A little more info is in order. If your building has only 208V 3-phase wye service then that’s all you have. There is no neutral in that system. That would mean no 120V single phase. So how is your building Illuminated?

I would guess that what you have is a 3-phase, 4-wire wye. That will provide 208V 3 phase and 120V single phase but no 240V single phase.

 

[grampamark]

If your building has a 3-phase, 4-wire system, you can have it all-208 3-phase, 240 3-phase, 240 single phase and 120 single phase. Our grain storage facility has such a system, but it was installed about 70 years ago when such designs were more common.

 

[SanPancho]

I love it when someone asks a question and then argues with the answer.

A little more info is in order. If your building has only 208V 3-phase wye service then that’s all you have. There is no neutral in that system. That would mean no 120V single phase. So how is your building Illuminated?

I would guess that what you have is a 3-phase, 4-wire wye. That will provide 208V 3 phase and 120V single phase but no 240V single phase.View attachment 724275

and i love it when people tell me things they clearly have no familiarity with AS FACT. but now it seems you've finally googled yourself into admitting i actually know what kind of power my system is being supplied by utility. thank you. so, for the record, we have 208wye 3phase power. and we have neutral.

now beyond that, if what you're trying to say is that my 2 hots with a neutral is still only getting me 208v then that's different, and thats bad news. i know some our equipment is the usual 208/240 rated stuff, but others we have with a single rating of 240v work fine. granted they may be running slower/less power/etc, but there are definitely things we've used that would NOT work, so its a bit confusing on that end for single phase gear. somebody could have meant they wired it a 208/220/240 type power and just casually said "240" without being specific, i.e. 208, 230/etc.

at the end of the day all i care about is knowing is if a single hot and a neutral does 120, is adding the 2nd hot bringing me another 120 or just creating 208 between them both? (given we're 208wye supply) that's the summation of my question. my understanding is that we got 240 by adding the 120+neutral to another leg. on the diagram above it'd be B and neutral and C. but from what you're saying it sounds like that isnt ACTUALLY 240v, but our system's version of "200" series voltage power which is still only actually 208v. its the added neutral leg that is making it unclear to me in this situation.

 

[Joeywhat]

There's no need for a neutral with a 208 wye, you get the 208 volts between two phases. Neutral would be needed if 120v was also needed (phase to neutral would be 120).

Having the neutral doesn't change the voltage between any of the phases, it'll still be 208 between them whether the neutral is there or not.

 

[passedpawn]

at the end of the day all i care about is knowing is if a single hot and a neutral does 120, is adding the 2nd hot bringing me another 120 or just creating 208 between them both? (given we're 208wye supply) that's the summation of my question. my understanding is that we got 240 by adding the 120+neutral to another leg. on the diagram above it'd be B and neutral and C. but from what you're saying it sounds like that isnt ACTUALLY 240v, but our system's version of "200" series voltage power which is still only actually 208v. its the added neutral leg that is making it unclear to me in this situation.

In single phase 120V, voltage between a single hot and a neutral is 120V. That's true in split phase and in 3-phase.
In 3-phase, voltage between two legs is 208V. Why isn't it 240V? In 3 phase, the two phases aren't 180° out of phase, but 120°. sin(120°) x 240V = 208V
In 3-phase, if you have a neutral, there is always 120V between any phase and that neutral.

 

[SanPancho]

right, im getting that impression.

for some reason i have it in my head that the existence of the neutral (H1, H2, N) means its 120 AND 120, not the 208 between phases.

either way, no bueno for us. seems my choice is either i have to add another port to kettle and run three single phase 208 circuits on the wall, with three elements/cords/outlets/gfci breakers, or just bore out the existing ports for 2" TCs and go with two 6k elements (rated based on 208v 3p).

 

[passedpawn]

Not sure what you're trying to do here, but if it's a big pot, skip the neutral and put three elements in there.

What is the wire gauge / amperage?

 

[SanPancho]

wires and amps arent the issue. its getting enough power to roll a 75-80 gal boil given constraints of kettle diameter/element spacing/etc. three 5500w elements run at 208 gives me 12.3ish kw. (de-rated to about 4100w each)
i've spec'd two elements at 208 three phase that give me 12kw. both options should give us a decent boil if we're patient.

i'll have to just run up a shopping list. my initial thoughts are that setting up two should be cheaper than three, but you never know. dealing with 3phase gear can be hit or miss in the saving money department.

 

[passedpawn]

haha, good luck.

 

[TheBluePhantom]

A little more info is in order. If your building has only 208V 3-phase wye service then that’s all you have. There is no neutral in that system. That would mean no 120V single phase. So how is your building Illuminated?

A wye system can have a neutral, a delta does not. It all depends if you run the neutral wire. You can just ground the center for a balanced delta, but calling it a wye implies a neutral.

i'll have to just run up a shopping list. my initial thoughts are that setting up two should be cheaper than three, but you never know. dealing with 3phase gear can be hit or miss in the saving money department.

Run the numbers, if you have to increase all the wire sizes and switchgear to pull the wattage on two hots, that sometimes increases the cost to higher than 3 phase. Also look at the physical size of the elements, if you have more surface area on three rather than two, less scorching. You may be happier with 208 for that reason....

 

[Joeywhat]

right, im getting that impression.

for some reason i have it in my head that the existence of the neutral (H1, H2, N) means its 120 AND 120, not the 208 between phases.

either way, no bueno for us. seems my choice is either i have to add another port to kettle and run three single phase 208 circuits on the wall, with three elements/cords/outlets/gfci breakers, or just bore out the existing ports for 2" TCs and go with two 6k elements (rated based on 208v 3p).

It IS 120 & 120 between two different phases and neutral... But you don't get to add them together to get your 240v you want. That only works when your incoming power supply is 240 volts (typical household supply power). Since you have 208 wye, you only get 208 volts between your hot phases.

Now, some 208 systems have a "wild leg" in which the phase to phase between one leg and either of the other two is 240v, while it's 208 between the other two... But I believe that is only in delta, not wye. If you're 100% sure you have wye then this isn't a possibility for you (and isn't seen often anyways). This is also a situation where a delta configuration will have a neutral.

 

[brymb5]

You might consider the services of a capable commercial electrician.
If your goal is to heat faster a third element is most likely the more economical depending on the length of wire/ conduit from the service panel. A buck/boost transformer can be installed to increase the 208v to 240v, but you can pull a lot of #8 wire before you exceed the cost of installing the transformer.

 

[SanPancho]

yeah, this is literally just gonna be a spreadsheet situtation. we have plenty of amps in panel, and the entire run is probably only 10, maybe 15 feet. but costs are all over the place.

the main issue i'm seeing so far as that there's not really a gfci option for the 3ph elements. which is a little concerning. actually alot concerning. but that means the 3pole breaker is only 50 bucks. vs more like almost 100 for gfci breakers at 30A DPST.

elements, and breakers for 3ph on their own are about 400.
three GFCI breakers and 3 elements from china are about 450 for single phase.
little boost transformer is nearly 300 for 45ish amp version.

so it looks like ex- wiring costs the single phase is about the same, but has gfci protection. seems like the way to go.

 

[SanPancho]

now here is something interesting i just ran across - 6500w element, ripple style, and a rough calculation says i should get about 4900w out of them at 208v
6500w dernod element

random online calculator says to take 75 gals of water from 150 to 212 is gonna run about 75 minutes if i was to run two of these guys at 4900w.

now here's where i could use some advice from electric users- that calculator assumes you have all 75 gals in the kettle before you hit the power. obviously not the case. i could probably cover the elements and hit the power at maybe 20-25 gallons. given that you'd be powering a much smaller volume at the beginning, is it safe to say i could cut the boil time in half? by a third? based on direct fire experience that would seem to make sense....

 

[Bobby_M]

wires and amps arent the issue. its getting enough power to roll a 75-80 gal boil given constraints of kettle diameter/element spacing/etc. three 5500w elements run at 208 gives me 12.3ish kw. (de-rated to about 4100w each)
i've spec'd two elements at 208 three phase that give me 12kw. both options should give us a decent boil if we're patient.

i'll have to just run up a shopping list. my initial thoughts are that setting up two should be cheaper than three, but you never know. dealing with 3phase gear can be hit or miss in the saving money department.

Granted understanding 3 phase is not intuitive. It starts getting into the topic of electrical engineering and understanding how AC current works. The reason why 120 +120 = 208 is the same reason why bouncing audio waves in a room will sometimes cancel out and you lose whole frequency spectrums.

I see you posted about Dernord elements but if you're concerned about safety I'd skip them. The wiring area is a hollow plastic shell and the ground prongs will likely pop their spot weld. We pot ours with epoxy to keep that mechanical stress under control. I have 7000 watt ripple elements. If you run them on 208 volts, you'll get 5256 watts out of it.

 

[Bobby_M]

Skipping the long formula, here are some ideas.

10512 watts is 35,868 BTU/hr

75 gallons all sitting at 150 will take about 65 minutes to go 150 to boiling.
If you're fly sparging to fill a kettle with 75 gallons, you'll want it to take an hour anyway so yes you'll be boiling all the way up. In fact, I could never figure out a good reason not to start the boil timer and hopping schedule when only half the preboil volume as been achieved.

 

[RiverCityBrewer]

Maybe I missed it as part of the discussion, but why not use elements designed for 208v?

https://ebrewsupply.com/collections/elements

 

[augiedoggy]

Maybe I missed it as part of the discussion, but why not use elements designed for 208v?

https://ebrewsupply.com/collections/elements

I was going to suggest the same... something like, 208v 3-phase 9kw Element. there were also options on alibaba when I last looking. I bought my elements from Yuling in china and I believe they could make most configurations if asked... would be worth trying since I paid $31 a piece with shipping for my elements vs $250... I am sure they make 208v 5500w elements too

you can also go with a buck-boost transformer to boost the power to 240v. they are used commonly on the equipment I work on to allow the 4,000watt UV lamp ballasts to work correctly as they wont on 208v