Wiring for 240 volt properly

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thekraken

thekraken

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So my main breaker panel is on the same wall that I want my 240 volt recepticle. I figure that the most economical way to do this is to use a 50 amp (type ch) breaker within the panel and attach that to a 50 amp gfi spa panel... right?

For a slightly cleaner install I could purchase a 50 amp type ch spa panel, remove the breaker from it and place it in my main panel... right?

Either way, my main panel is flush mounted in the wall and the wall has dry wall, what is the *best* way to actually run the wire out of the main panel and to surface mounted conduit? In other words, how should I actually get my wire out of there?

As you'll see the main panel is in the wall with 2x4 on either side, a crap ton of wires up top, and not much room to work with between the bottom and the floor.
7CT2SGy.jpg

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What actual pieces should be used to make the wall penetration?

I've got everything else figured out, what I need to know now is the proper way to transition from my knockout hole in my *in wall* panel to my *surface mounted* conduit. It's the last piece of the puzzle.

If the main panel were only surface mounted I wouldn't be asking, I'd be running conduit by now!
 
thekraken said:
What actual pieces should be used to make the wall penetration?

I've got everything else figured out, what I need to know now is the proper way to transition from my knockout hole in my *in wall* panel to my *surface mounted* conduit. It's the last piece of the puzzle.

If the main panel were only surface mounted I wouldn't be asking, I'd be running conduit by now!
Click to expand...

You can use romex connectors like these, https://www.google.com/search?q=romex+connector&ie=utf-8&oe=utf-8#q=romex+connector&tbm=shop to run the 6 gauge from you main panel breaker through the knockout and another set of them on the knockouts of your surface panel... There is no need for you to install any type of protective conduit or BX for such a short cable run being that it directly below the main box... I know know if that what your asking for sure?

My installation wasnt so straight forward... my main panel is much more crowded and I do not have that convenient main breaker in mine... This made my installation more like playing the "operation" game... only one dumb move and im dead..
 
If it's outside of the wall and 'exposed' it wouldn't require protection by code? Or are you saying run the romex through the back of the surface mounted panel?

(Also, the operation reference made me chuckle, I'm glade you pulled through)
 
thekraken said:
If it's outside of the wall and 'exposed' it wouldn't require protection by code? Or are you saying run the romex through the back of the surface mounted panel?

(Also, the operation reference made me chuckle, I'm glade you pulled through)
Click to expand...

my drawing shows running the wire in a conduit

I would...run 1'' pvc conduit, out the old panel,out the wall

then run the conduit to the bottom of the your new box

lock nut for male adapter

use the lock nuts, to keep from nicking the wire

I would not run romex exposed. might get snagged or something


conduit clamp
 
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unless there is a local ordinance stating otherwise, there is no need to install conduit. it is acceptable to do so but not required. the advantage in not running conduit is that the wall doesn't need to be all cut up. cut a small hole in the drywall, fish nm cable from the main panel through the hole in the drywall, create an opening in the rear of the spa panel, install nm connectors at the main panel and the spa panel, mount the spa panel to the wall using drywall anchors. done.

if installing conduit, a good chunk of the wall will need to be removed to provide access for installing the conduit. then the wall repair involves taping, mudding, sanding, painting, etc.
 
odorf said:
my drawing shows running the wire in a conduit

I would...run 1'' pvc conduit, out the old panel,out the wall

then run the conduit to the bottom of the your new box

lock nut for male adapter

use the lock nuts, to keep from nicking the wire

I would not run romex exposed. might get snagged or something
Click to expand...

1" just because it would be easier to work with? (I'm figuring about 270 deg of bend by the time we get to the sub panel) 3/4" would be the minimum size for 4x 6awg conductors right?
 
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thekraken said:
1" just because it would be easier to work with? (I'm figuring about 270 deg of bend by the time we get to the sub panel) 3/4" would be the minimum size for 4x 6awg conductors right?
Click to expand...



yep, it would be easier to push wire. 3/4 will work it will be a pita going around them 90s


pull a 12 gauge wire with it for future expansion LOL
 
odorf said:
pull a 12 gauge wire with it for future expansion LOL
Click to expand...

I was indeed thinking of running another 20amp circuit too just because my garage needs one. Your laughter has my a little confused, so is it okay for me to run the second circuit in the same conduit? I was assuming I'd run another pvc conduit next to this 50 amp, not necessary?
 
assuming this is a 2x4 wall, you won't even be able to get 90 degree pvc fittings that will fit in the wall. conduit is a mistake for this application, just go with the nm.
 
itsnotrequired said:
assuming this is a 2x4 wall, you won't even be able to get 90 degree pvc fittings that will fit in the wall. conduit is a mistake for this application, just go with the nm.
Click to expand...

Okay, but do I understand that you are saying the romex will not be exposed between the panels, you propose it will all still be fished behind the wall?

Regarding the 2x4, there are studs on either side of the main panel but not above or below. Though the top side is already crowded.
 
thekraken said:
I was indeed thinking of running another 20amp circuit too just because my garage needs one. Your laughter has my a little confused, so is it okay for me to run the second circuit in the same conduit? I was assuming I'd run another pvc conduit next to this 50 amp, not necessary?
Click to expand...

I had an electrician wire my garage after having it built about 15 years ago... they did not use any conduit and my walls are open exposing the romex to the light of day.... its actually safer exposed than hidden in the walls if you think about it since people are less likely to screw or nail into it... now when I ran the 60 amp service outside for my hot tub , that needed to be in outdoor rated conduit and it was not fun to do.

You really dont need to use conduit unless its a commercial application from what I remember... I am not an electrician but I know enough to get by I worked as a maintenance man for years and dealt with a lot of "old work"

most people who have older homes have a surface mounted box on their basement wall with lots of exposed romex running into it... unless Edward scissor hands lives there it will be fine, Just saying..
 
augiedoggy said:
I had an electrician wire my garage after having it built about 15 years ago... they did not use any conduit and my walls are open exposing the romex to the light of day.... its actually safer exposed than hidden in the walls if you think about it since people are less likely to screw or nail into it... now when I ran the 60 amp service outside for my hot tub , that needed to be in outdoor rated conduit and it was not fun to do.

You really dont need to use conduit unless its a commercial application from what I remember... I am not an electrician but I know enough to get by I worked as a maintenance man for years and dealt with a lot of "old work"

most people who have older homes have a surface mounted box on their basement wall with lots of exposed romex running into it... unless Edward scissor hands lives there it will be fine, Just saying..
Click to expand...


the LOL was in reference to you might expand.

when we both know you WILL expand

He is correct, conduit is not required by code.

i like using conduit
 
thekraken said:
Okay, but do I understand that you are saying the romex will not be exposed between the panels, you propose it will all still be fished behind the wall?

Regarding the 2x4, there are studs on either side of the main panel but not above or below. Though the top side is already crowded.
Click to expand...

where will you be locating your spa panel and receptacle? both below your main panel? that's what my previous comments were based on.
 
augiedoggy said:
Mine too since that is what he originally stated.
Click to expand...

Hey now, I never said that ;)

Okay how about this, here is a drawing of what my entire wall looks like right now. Where and how would YOU locate your conduits/spa panels/50 amp receptacle

rzQcoOc.png


(I'm planning to make the whole wall a long workbench with the far right end being my brewery area, the right edge is the garage door)
 
You could always run romex from the breaker down through a knockout and out through a hole in the drywall and the back of a surface mounted junction box. From there you could run conduit anywhere you want.
 
laradactyl said:
You could always run romex from the breaker down through a knockout and out through a hole in the drywall and the back of a surface mounted junction box. From there you could run conduit anywhere you want.
Click to expand...

Does the romex have to have strain relief coming out of the knockout of the main panel? I'm wondering if I would prefer to go out the right side of the main panel, through the 2x4, to avoid putting the junction so close to the ground.
 
thekraken said:
Does the romex have to have strain relief coming out of the knockout of the main panel? I'm wondering if I would prefer to go out the right side of the main panel, through the 2x4, to avoid putting the junction so close to the ground.
Click to expand...

I would have figured that some electrician would have stepped in and answered that question for you. My guess is that NEC would probably require you to use a strain relief but I know little to nothing about code. Though I have years of experience with electricity I have had very limited exposure to the National Electric Code. I have run more conduit and conductor than most electricians my age but it was all for either the military, municipalities, or utilities, none of which allowed National Electric Code rules to influence their engineers and technicians.
 
yes, the nm cable will need to be restrained at the main panel and at the spa panel (cable clamps, strain relief, etc.).

based on the situation, i would recommend surface-mounting the spa panel below the main panel (in the same wall cavity). run conduit or wiremold from the spa panel to a surface-mounted receptacle for your brew panel. either pvc or emt is acceptable. do you plan on a 30 amp or 50 amp brew panel? that will dictate the size conduit and conductors required.
 
itsnotrequired said:
yes, the nm cable will need to be restrained at the main panel and at the spa panel (cable clamps, strain relief, etc.).

based on the situation, i would recommend surface-mounting the spa panel below the main panel (in the same wall cavity). run conduit or wiremold from the spa panel to a surface-mounted receptacle for your brew panel. either pvc or emt is acceptable. do you plan on a 30 amp or 50 amp brew panel? that will dictate the size conduit and conductors required.
Click to expand...

Well, I figure I may as well go for 50 right?

I'm figuring 6 awg for the 50 amp, and either 12 awg or 10 awg for the new 20 amp circuit depending on weather or not I run the wires through the same conduit (5 conductor derating). THHN/THWN/THWN-2 wire for the conduit runs. So 'worst case' using one 3/4" pvc conduit gives me 38% fill. Sound about right? (I understand that ground wire doesn't count toward conduit fill, can anyone confirm?)

But I can't help but wonder if at this point it would just be cheaper to strategically open the wall up and forgo conduit. I have access to the attic above.
 
thekraken said:
Well, I figure I may as well go for 50 right?

I'm figuring 6 awg for the 50 amp, and either 12 awg or 10 awg for the new 20 amp circuit depending on weather or not I run the wires through the same conduit (5 conductor derating). THHN/THWN/THWN-2 wire for the conduit runs. So 'worst case' using one 3/4" pvc conduit gives me 38% fill. Sound about right? (I understand that ground wire doesn't count toward conduit fill, can anyone confirm?)

But I can't help but wonder if at this point it would just be cheaper to strategically open the wall up and forgo conduit. I have access to the attic above.
Click to expand...

you really only need 50 amp if you are looking to use large elements or back-to-back batches. assuming you want the full 50 amps with a three-wire circuit (two hots and a neutral), you would be looking at minimum #6 awg ungrounded and grounded conductors (hots and neutral) and a minimum #10 awg equipment grounding conductor (egc, assumes you are running thhn). you would need a 3/4" conduit for those four conductors but that is the bare minimum. 1" conduit would make for easier pulls. these conduit sizes apply to both emt or pvc.

for the receptacle ciruit, that could be a dedicated 1/2" conduit, whether you use #12 or #10. as mentioned above, #10 is overkill and depending on the size of the single-gang boxes the receptacles would be mounted in, you could very will exceed the allowable fill of the box (the volume taken up by the conductors, wire nuts, receptacles, etc. in the box). #10 is harder to bend than #12 and if the box is filled to capacity, it makes for an ugly installation. no real reason to do this and could result in a code violation.

if you want to have a portion of conduit with both the 50 amp and 20 amp circuits, you would need to run minimum 1" conduit, whether emt or pvc (again, with thhn conductors). it would be 1" even if you ran #10 for the 20 amp circuit. it would be 1" conduit from the spa panel to the first receptacle box. from there, the circuits would split into separate conduit runs. note that the first box would need to be two-gang, to accommodate all the conductors. also note that both the 50 amp and 20 amp circuits can share a single #10 egc to that first box. from there, #10 would need to continue with the 50 amp circuit and #12 could run off to the 20 amp circuit (would need to be #10 if the hot/neutral are #10). you could run a full-size #6 egc for the 50 amp circuit and you would still only need 1" conduit.

regarding ampacity derate, the egc does not count as a current carrying conductor (but does count toward conduit fill). the neutral counts if carrying more than unbalanced current. so it would count for two-wire single phase circuit. assuming you have 120 volt loads at your brew panel, that neutral would count as well. so looking at a maximum of five current carrying conductors in a single raceway, resulting in an 80% amapacity derate. however, we are allowed to take advantage of the 90 degree c ampacity column for derating purposes. for these size conductors, the 80% derate ampacity at the 90 degree c values is greater than the 60 degree c column ampacity values with no derate. in other words, no need to increase your conductor sizes to account for derate.
 
itsnotrequired said:
you really only need 50 amp if you are looking to use large elements or back-to-back batches. assuming you want the full 50 amps with a three-wire circuit (two hots and a neutral), you would be looking at minimum #6 awg ungrounded and grounded conductors (hots and neutral) and a minimum #10 awg equipment grounding conductor (egc, assumes you are running thhn). you would need a 3/4" conduit for those four conductors but that is the bare minimum. 1" conduit would make for easier pulls. these conduit sizes apply to both emt or pvc.

for the receptacle ciruit, that could be a dedicated 1/2" conduit, whether you use #12 or #10. as mentioned above, #10 is overkill and depending on the size of the single-gang boxes the receptacles would be mounted in, you could very will exceed the allowable fill of the box (the volume taken up by the conductors, wire nuts, receptacles, etc. in the box). #10 is harder to bend than #12 and if the box is filled to capacity, it makes for an ugly installation. no real reason to do this and could result in a code violation.

if you want to have a portion of conduit with both the 50 amp and 20 amp circuits, you would need to run minimum 1" conduit, whether emt or pvc (again, with thhn conductors). it would be 1" even if you ran #10 for the 20 amp circuit. it would be 1" conduit from the spa panel to the first receptacle box. from there, the circuits would split into separate conduit runs. note that the first box would need to be two-gang, to accommodate all the conductors. also note that both the 50 amp and 20 amp circuits can share a single #10 egc to that first box. from there, #10 would need to continue with the 50 amp circuit and #12 could run off to the 20 amp circuit (would need to be #10 if the hot/neutral are #10). you could run a full-size #6 egc for the 50 amp circuit and you would still only need 1" conduit.

regarding ampacity derate, the egc does not count as a current carrying conductor (but does count toward conduit fill). the neutral counts if carrying more than unbalanced current. so it would count for two-wire single phase circuit. assuming you have 120 volt loads at your brew panel, that neutral would count as well. so looking at a maximum of five current carrying conductors in a single raceway, resulting in an 80% amapacity derate. however, we are allowed to take advantage of the 90 degree c ampacity column for derating purposes. for these size conductors, the 80% derate ampacity at the 90 degree c values is greater than the 60 degree c column ampacity values with no derate. in other words, no need to increase your conductor sizes to account for derate.
Click to expand...

I am very impressed to see an electrician that understands derating. I'm even more impressed the you mention you can use the 90 c column for derating even though i'm sure every lug in the circuit is 75 c. This I was not aware of. But makes complete sense and I'm having a why the hell did I not know that moment.

As far as this installation. Just but the damn thing under the panel and run conduit from it. Or run romex through the attic and drop down to your control panel. Just sleeve the romex that is exposed with conduit to protect it from physical damage.
 
It never takes long for me to remember why I try to avoid posting anything in an electrical thread.
 
itsnotrequired said:
you really only need 50 amp if you are looking to use large elements or back-to-back batches. assuming you want the full 50 amps with a three-wire circuit (two hots and a neutral), you would be looking at minimum #6 awg ungrounded and grounded conductors (hots and neutral) and a minimum #10 awg equipment grounding conductor (egc, assumes you are running thhn). you would need a 3/4" conduit for those four conductors but that is the bare minimum. 1" conduit would make for easier pulls. these conduit sizes apply to both emt or pvc.

for the receptacle ciruit, that could be a dedicated 1/2" conduit, whether you use #12 or #10. as mentioned above, #10 is overkill and depending on the size of the single-gang boxes the receptacles would be mounted in, you could very will exceed the allowable fill of the box (the volume taken up by the conductors, wire nuts, receptacles, etc. in the box). #10 is harder to bend than #12 and if the box is filled to capacity, it makes for an ugly installation. no real reason to do this and could result in a code violation.

if you want to have a portion of conduit with both the 50 amp and 20 amp circuits, you would need to run minimum 1" conduit, whether emt or pvc (again, with thhn conductors). it would be 1" even if you ran #10 for the 20 amp circuit. it would be 1" conduit from the spa panel to the first receptacle box. from there, the circuits would split into separate conduit runs. note that the first box would need to be two-gang, to accommodate all the conductors. also note that both the 50 amp and 20 amp circuits can share a single #10 egc to that first box. from there, #10 would need to continue with the 50 amp circuit and #12 could run off to the 20 amp circuit (would need to be #10 if the hot/neutral are #10). you could run a full-size #6 egc for the 50 amp circuit and you would still only need 1" conduit.

regarding ampacity derate, the egc does not count as a current carrying conductor (but does count toward conduit fill). the neutral counts if carrying more than unbalanced current. so it would count for two-wire single phase circuit. assuming you have 120 volt loads at your brew panel, that neutral would count as well. so looking at a maximum of five current carrying conductors in a single raceway, resulting in an 80% amapacity derate. however, we are allowed to take advantage of the 90 degree c ampacity column for derating purposes. for these size conductors, the 80% derate ampacity at the 90 degree c values is greater than the 60 degree c column ampacity values with no derate. in other words, no need to increase your conductor sizes to account for derate.
Click to expand...

Tons of good info, than you very much.

Okay, so counting the ground toward fill puts me at 29% fill for 1" pvc conduit.

So you were saying that my 50 amp circuit only needs 10awg ground?

Also, I was figuring the ampacity derate to 10awg based on this data. I've actually seen conflicting data so I thought it best to go with the worst case. Does the table your referring to come from the code book? That would obviously trump and make me sleep better...
 
thekraken said:
Tons of good info, than you very much.

Okay, so counting the ground toward fill puts me at 29% fill for 1" pvc conduit.

So you were saying that my 50 amp circuit only needs 10awg ground?
Click to expand...

assuming three #6 conductors (two hots and a neutral for the 50 amp circuit), two #12 conductors (hot and neutral for the 20 amp circuit) and a #10 egc, the cross-sectional area of these conductors is 0.2187 in sq. 1" schedule 40 pvc has a 0.832 in sq cross-sectional area or a touch over 26% fill. if you ran 1" emt, you would be a touch over 25% full (emt has a smaller sidewall thickness compared to pvc). since there are more than two wires in the conduit, maximum allowable fill is 40%.

and yes, a #10 egc is allowed on a 50 amp circuit. hell, #6 nm cable is constructed with an integral #10 egc.
 
Kh2o said:
I am very impressed to see an electrician that understands derating. I'm even more impressed the you mention you can use the 90 c column for derating even though i'm sure every lug in the circuit is 75 c. This I was not aware of. But makes complete sense and I'm having a why the hell did I not know that moment.
Click to expand...

it is the thhn conductor that let's us get away with it. if it was thwn, we would be stuck with the 75 degree c derate but do they even make thwn conductor that doesn't also carry a thhn rating?

note that nm cable also gets to take advantage of the 90 degree c derate values, even though it is limited to 60 degree c ampacity for continuous operation :mindblown:
 
itsnotrequired said:
assuming three #6 conductors (two hots and a neutral for the 50 amp circuit), two #12 conductors (hot and neutral for the 20 amp circuit) and a #10 egc, the cross-sectional area of these conductors is 0.2187 in sq. 1" schedule 40 pvc has a 0.832 in sq cross-sectional area or a touch over 26% fill. if you ran 1" emt, you would be a touch over 25% full (emt has a smaller sidewall thickness compared to pvc). since there are more than two wires in the conduit, maximum allowable fill is 40%.

and yes, a #10 egc is allowed on a 50 amp circuit. hell, #6 nm cable is constructed with an integral #10 egc.
Click to expand...

Cool, #10 ground it is.
And just because it appears you replied to me previous comment before I edited it I'll copy and paste: "I was figuring the ampacity derate to 10awg based on this data (and was indeed looking for 90c). I've actually seen conflicting data so I thought it best to go with the worst case. Does the table your referring to come from the code book?"
 

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