Will these 220 outlets pass wiring inspection?

[ybnormal70]

Any help is greatly appreciated.

I'm wiring 3 6-50r in a chain on 1 50 amp circuit. I'm using 3/4" conduit, 4x4x2-1/8" boxes, #8 red and black for hots and #10 green for grounds.

I know my conduit fill is fine. Just wanting to make sure that the box wiring is correct.

Thanks,

Kevin

 

[jjpp]

They all have to be on separate circuits on their own breakers to be code. You can't daisy chain 240v receptacles.

 

[ybnormal70]

Numerous sources say otherwise on here and elsewhere.

"There is no limit on the maximum number of receptacles allowed on a single branch circuit, either 120 or 240V."

I do know that local code can dictate this but do you have a code that specifies this?

Thanks,

Kevin

 

[alfredeneuman]

It should be fine.

You're allowed (10) #8s in a 4"X2-1/8" box.
You only have 6 ones that are applicable.
Receptacles count as 2, so that would be 8.
With the #10 grounds, it would be right near the limit.

"They all have to be on separate circuits on their own breakers to be code. You can't daisy chain 240v receptacles."
This is wrong.

NEC 210.21(B)(3)
Receptacle Ratings. Where connected to a branch circuit
supplying two or more receptacles or outlets, receptacle
ratings shall conform to the values listed in Table
210.21(B)(3), or, where rated higher than 50 amperes, the
receptacle rating shall not be less than the branch-circuit
rating.

This seems to allow it.

 

[devoncoolman]

Looks good to me. You would have to check local code for daisy chaining. U can do it you just have to know your load. You cant run to many things off that run you will blow the breaker.

 

[ybnormal70]

It will only be used for 1 item at a time. It's just my personal garage. Air compressor will be on a dedicated circuit.

Local told told me we go by 2012 IRC code. Anyone know if that has anything about this specific question?

Thanks,

Kevin

 

[pattenp]

Don't know about South Carolina, but Virginia residential building code does not allow multiple outlets on on a single circuit that's more than 20 amps at 120V. So your local code may limit the number of 240V outlets on a circuit.

 

[bigbluthng]

is the box grounded?

 

[66dave]

is the box grounded?

My thoughts exactly. The one advantage of conduit is that the system is all grounded by the metal structure, so why are you running grounds thru the tubing? Nothing wrong with that, but it lowers the number of conductors in the tube.

What toys are you plugging in? You have to share some pictures...

 

[MN4x4]

is the box grounded?

The pictures don't make it easy to see, but it sure looks like he has 4 ground wires, so:

1 in
1 out
1 to receptacle
1 to box

Unless local code restricts it, he's right on the line with fill but perfectly within code.

 

[wyliesdiesels]

Just wht will u be plugging into these outlets?

 

[ybnormal70]

Yes they are all grounded with #10 stranded wire with a ring terminal connecting it to each box. I have several items that are 220. I have a table saw, air compressor, welder and a scissor lift. Air compressor will be on a dedicated circuit and the other items won't even be plugged in unless I am using them. Just want to be able to position them where I need them.

This is the only code in the 2012 IRC that I could find that mentions it but it is stating for a "dwelling". I'm not certain if my "detached garage" is considered a "dwelling" or not:

"E3702.5 Branch circuits serving multiple loads or outlets.
General-purpose branch circuits shall supply lighting outlets, appliances, equipment or receptacle outlets, and combinations of such. Multi-outlet branch circuits serving lighting or receptacles shall be limited to a maximum branch-circuit rating of 20 amperes."

Any ideas?

Thanks,

Kevin

 

[laser3kw]

you may want to turn the air compressor off while using the other items. If you are welding or using the saw, the surge of the air compressor may kick the breaker.

 

[ybnormal70]

"Air compressor will be on a dedicated circuit".

Already taken care of.

Kevin

 

[pattenp]

That's the same code we have in Virginia but is listed as residential use. If your wording elsewhere is saying applies to dwellings only then may be that's your loophole if the garage/shop is detached. If you're having it inspected why not call your local electrical inspector?

Yes they are all grounded with #10 stranded wire with a ring terminal connecting it to each box. I have several items that are 220. I have a table saw, air compressor, welder and a scissor lift. Air compressor will be on a dedicated circuit and the other items won't even be plugged in unless I am using them. Just want to be able to position them where I need them.

This is the only code in the 2012 IRC that I could find that mentions it but it is stating for a "dwelling". I'm not certain if my "detached garage" is considered a "dwelling" or not:

"E3702.5 Branch circuits serving multiple loads or outlets.
General-purpose branch circuits shall supply lighting outlets, appliances, equipment or receptacle outlets, and combinations of such. Multi-outlet branch circuits serving lighting or receptacles shall be limited to a maximum branch-circuit rating of 20 amperes."

Any ideas?

Thanks,

Kevin

 

[ybnormal70]

I've called local office numerous times. Everytime they transfer to someone's voicemail and no one has called me back yet.

Kevin

 

[fnsane]

I'm sort of confused here. You are using 8awg for a 50 amp circuit, is that correct? If so, what source tells you that is good to go?

Fnsane

 

[ybnormal70]

What Is the Ampacity for #8 AWG THHN?
Allowable Ampacity: 40 Amps at 60ºC / 50 Amps at 75ºC / 55 Amps at 90ºC

When installed in conduit you use the 75ºC column for max amp rating.

Kevin

 

[fnsane]

Why are you using 8awg for 50 amp circuit?

Fnsane

 

[fnsane]

What Is the Ampacity for #8 AWG THHN?
Allowable Ampacity: 40 Amps at 60ºC / 50 Amps at 75ºC / 55 Amps at 90ºC

When installed in conduit you use the 75ºC column for max amp rating.

Kevin

What is your reference source for that?

Fnsane

 

[ybnormal70]

https://ia600701.us.archive.org/Boo...12_jp2/icc.irc.2012_0730.jp2&scale=2&rotate=0

It looks like 8awg uses the 75°c column for thhn rated at 50amps.

This is from the 2012 IRC which is what my county uses for code.

Thanks,

Kevin

 

[Charles (in GA)]

Table 310.15(B)(16) of the 2011 NEC, 75°C column for Copper wire, individuals wires, not more than three current carrying wires in a raceway.

50 amps.

Charles

 

[Charles (in GA)]

https://ia600701.us.archive.org/Boo...12_jp2/icc.irc.2012_0730.jp2&scale=2&rotate=0

Actually it looks like 8awg uses the 90°c column for thhn rated at 55amps.

This is from the 2012 IRC which is what my county uses for code.

Thanks,

Kevin

You cannot use the 90°C column for determining the amperage because the connections at the ends, such as circuit breaker, the receptacles, etc, are only 75°C rated. The 90° column can be used for calculating derating and such, but not for initial amp capacity. You have to go with the lowest rated component of the circuit, and I think the code tells you to use the 75° column no matter the wire rating.

EDIT: Others are correct 110.14(C)(1)(a)(1) and (2) tell you to use the 60°C rating of the wire for determining ampacity.

Charles

 

[ybnormal70]

Ok thanks. I'm honestly still not sure if I can pass because of the branch circuit over 20amp statement. I guess I will find out Monday if I can get an inspector on the phone. I'm just hoping that dwelling won't include my detached garage .

Kevin

 

[wyliesdiesels]

What is your reference source for that?

Fnsane

Dude, google NEC 310.15(b)(16). #8 THHN has an ampacity of 50a

https://ia600701.us.archive.org/Boo...12_jp2/icc.irc.2012_0730.jp2&scale=2&rotate=0

Actually it looks like 8awg uses the 90°c column for thhn rated at 55amps.

This is from the 2012 IRC which is what my county uses for code.

Thanks,

Kevin

The 90* c column is for derating purposes only!

EDIT: charles beat me to it!

 

[Bib Overalls]

Leave one 220 outlet on the circuit and hide the rest in the attic until the inspection is over.

 

[Gooch]

It should be fine.

You're allowed (10) #8s in a 4"X2-1/8" box.
You only have 6 ones that are applicable.
Receptacles count as 2, so that would be 8.
With the #10 grounds, it would be right near the limit.

"They all have to be on separate circuits on their own breakers to be code. You can't daisy chain 240v receptacles."
This is wrong.

NEC 210.21(B)(3)
Receptacle Ratings. Where connected to a branch circuit
supplying two or more receptacles or outlets, receptacle
ratings shall conform to the values listed in Table
210.21(B)(3), or, where rated higher than 50 amperes, the
receptacle rating shall not be less than the branch-circuit
rating.

This seems to allow it.

this receptacle would count as 4 as it mounts on 2 yokes. also IIRC the EGC doesn't count at all.

 

[ybnormal70]

I've wondered if I could just replace the breaker with a 20amp double-pole and leave the 6-50r receptacles . At least to pass inspection. I actually don't think I even need more than a 30amp for my items that are 220 honestly.

Air compressor is 16amps
Scissor lift is 20amps
MIG welder has max of 22amps

Not sure what to do at this point really. Can't hide anything as this is all exposed work in conduit along bare walls.

Kevin

 

[fnsane]

Guys, you use the 60 degree table below 1/0. above 1/0 use the 75 degree table. You only use the 90 degree table to derate.

Kevin, you are in SC. Correct?? I just happen to be a licensed General Contractor and Electrical Contractor in SC and several other states. I realize these forums are filled with folks who spend endless hours over minor details. Please believe me, use #6 copper for your 50 amp stuff. #10 grounds are correct. Only use the 60 degree tables.

Fnsane

 

[pattenp]

This is not totally correct. You are confusing terminal temperature ratings with conductor temperature. Most if not all devices carry a 60/75 C degree rating so 75C wire can be used in wire sizes smaller than 1/0. See NEC 110.14(c)(1) Unless equipment is listed/marked otherwise.

Guys, you use the 60 degree table below 1/0. above 1/0 use the 75 degree table. You only use the 90 degree table to derate.

Kevin, you are in SC. Correct?? I just happen to be a licensed General Contractor and Electrical Contractor in SC and several other states. I realize these forums are filled with folks who spend endless hours over minor details. Please believe me, use #6 copper for your 50 amp stuff. #10 grounds are correct. Only use the 60 degree tables.

Fnsane

 

[alfredeneuman]

this receptacle would count as 4 as it mounts on 2 yokes. also IIRC the EGC doesn't count at all.

As the picture indicates, the receptacle is mounted is on 1 yoke.
The grounding conductor is counted as 1 conductor.



ybnormal70, If the Building Dept. says you need separate circuit you could install them in the existing conduits with additional wires, but it would break the derating rules. Since you're planning not to use any of the outlets at the same time that would be a non-issue, but technically a Code violation.

I'd wait until you hear back from the Building Dept. before doing anything.

EDIT: The additional conductors would need to be pulled straight through the boxes without splices

 

[ybnormal70]

Waiting is my plan right now. I don't want to waste any more money than I might have already.

Thanks,

Kevin

 

[ybnormal70]

Here is exactly what I am wanting:

I want 1 row of 6 220 50 amp outlets. Except for code, I really only need 1 circuit as I will not be using more than 1 at a time. I will have other 220 outlets for dedicated stuff like compressor elsewhere.

What would I need to make this happen? Could I use my same boxes and just upgrade from the 3/4" conduit and go with 1" or maybe 1-1/4"? Would that work with these boxes?

Could I do as I asked earlier and just install a 20amp breaker so that the multi-outlet circuit is acceptable by code? Is a 20amp circuit ok to have 50amp outlets?

I'm at a loss now.

Thanks everyone,

Kevin

 

[alfredeneuman]

You'd be required to use 20 amp receptacles if you plan on reducing the breaker size.

(10) #8's will fit in a 3/4" EMT.
Any more than 3 would be derated to 44 amps or less, no matter what size of conduit you use.

 

[ybnormal70]

It sounds to me like I just need to install 1 outlet, get inspected and then finish. It seems that nothing I am doing would be unsafe, just against certain codes, not all codes, just happens to be the code here.

Decisions, decisions...

Kevin

 

[alfredeneuman]

You originally said 3, now it's increased to 6 ?

 

[ybnormal70]

3 is what was ran in the first pic. I'm wanting 6 total and was planning to hopefully do it the same was as originally pictured.

It was going to be 2 circuits ran individually with 3 outlets on each.

Kevin

 

[ybnormal70]

This was my original plan drawn out.

Kevin

 

[fnsane]

This is not totally correct. You are confusing terminal temperature ratings with conductor temperature. Most if not all devices carry a 60/75 C degree rating so 75C wire can be used in wire sizes smaller than 1/0. See NEC 110.14(c)(1) Unless equipment is listed/marked otherwise.

See NEC 110.14(c)(1)(a)(1-4) and give us your comments. Thanks,

fnsane

 

[ybnormal70]

http://www.mikeholt.com/onlinetraining/page_images/6_15_34_3_2.gif

NEC 2008 Article 110.14 (C):
The temperature rating associated with the ampacity of a conductor shall be selected and coordinated so as not to exceed the lowest temperature rating of any connected termination, conductor, or device. Conductors with temperatur ratings higher than specified for terminations shall be permitted to be used for ampacity adjustment, correction or both.


I'm not an electrician but to me that still looks like you can use 8awg and the 75°c column.

I'm not sure.

Kevin