# What type wire to use from transfer switch to outdoor outlet



## brjl (Dec 1, 2009)

I have installed a Connecticut Electric transfer switch for my generator (7500 watt) to my breaker panel and now I want to run wire from the switch 60 feet inside the house and hook up to an outlet (30 amp) that will be attached to an exterier wall of the house. I have purchase a rain tight outlet box, the only thing I need to do is run the wire into the back of it from the basement. 
The question is, I purchased 10/3 NM-B with ground wire, the wire has a white, black, red, and un-cased ground. Would this be the correct wire to use? I had the impression that I needed 10/4 wire, with the ground wire cased,(green) but the Home Depot person stated that since this is an interior installation, that the 10/3 is what I need. Is the 10/3 wire correct? The transfer swich has a red, black, white and green wire to hook to. 

Thanks for any help. 

Brian


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## MI-Roger (Aug 8, 2009)

*I suggest checking with your local code authority*

Check with your local authority. It is always cheaper to only have to do a job once.


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## kbsparky (Sep 11, 2008)

I would hope that you are considering installing an *inlet* for your transfer switch feed.


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## EBFD6 (Aug 31, 2008)

MI-Roger said:


> It sounds as if this run of wire will be the power feed into the home when no utility power is available and you are running off the generator. If so, the local code authority may consider this to be an alternate "Service Entrance" which will require all wires to be protected by conduit for a run of this length. You are prohibited from installing NM cable in conduit.
> 
> Check with your local authority. It is always cheaper to only have to do a job once.


This would not be classified as an alternate service entrance (a term I have never heard in my career) as the generator will have a main breaker on it, making the wiring feeding into the building a feeder cable not a service cable.

Secondly, service entrance cables are not required by the NEC to be protected by conduit for the entire run. It is not uncommon to do the entire service in SEU cable.

Thirdly, there is no prohibition in the NEC from running NM-B cable in conduit, with the exception of conduit outdoors. This has to do with the conduit installed outdoors being classified as a wet location and NM cable can not be installed in a wet location. Running NM-B in conduit indoors (dry location) is perfectly acceptable to the NEC, unnecessary unless it's for protection from physical damage, but code legal.

However, I too would suggest checking with the local inspector before starting the project if there are any questions.

Also, to echo what kbsparky said, make sure you use an inlet not an outlet. There is a big difference.


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## brjl (Dec 1, 2009)

EBFD6 said:


> This would not be classified as an alternate service entrance (a term I have never heard in my career) as the generator will have a main breaker on it, making the wiring feeding into the building a feeder cable not a service cable.
> 
> Secondly, service entrance cables are not required by the NEC to be protected by conduit for the entire run. It is not uncommon to do the entire service in SEU cable.
> 
> ...


 

When you say inlet, I am going to assume that you mean the box on the house will have the male end, and the cord have a female end, right?


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## brjl (Dec 1, 2009)

brjl said:


> When you say inlet, I am going to assume that you mean the box on the house will have the male end, and the cord have a female end, right?


 
Oh, never mind, the box that is being shipped is an inlet. 

Thanks for the help, I feel much more comfortable. 

Brian


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## anhconnho (Dec 2, 2009)

However, I too would suggest checking with the local inspector before starting the project if there are any questions.
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## EBFD6 (Aug 31, 2008)

brjl said:


> When you say inlet, I am going to assume that you mean the box on the house will have the male end, and the cord have a female end, right?


exactly!


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## coldfrigman (Nov 14, 2013)

*68 foot run??*

I read this post. My question is similar. I had to run a 68 ft length of 10/3 plus ground romex from the transfer switch to the inlet box in my garage. From there I have to use a 20 ft length of 30 amp, 10/3 cable to the generator. My generator is rated 7500Watts. Can I safely power my 10 circuits from my generator power switch, with this run and thickness of wire? I would only be powering 15 and 20 amp single pole circuits, like furnace, lights, frig, etc. I know about the 3 volts max voltage drop. I am confused when reading the voltage, watts, on line calculators. Thanks for any help.


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## Glennsparky (Nov 30, 2011)

coldfrigman said:


> ... I know about the 3 volts max voltage drop. ...


Not volts, percent. It's max 3% VD on the feeder and max 2% VD on the branch. Total 5% VD max, source to equipment.

3% is about 96 feet of 10/3 w/g cable (240V, 30A). 68+20=88' is still less than 96'. So it's fine. If you're done don't worry about it.

If you have doubts, upping the wire size on the romex only, would be a cost effective way to improve VD.


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## Philly Master (Mar 30, 2013)

brjl said:


> I have installed a Connecticut Electric transfer switch for my generator (7500 watt) to my breaker panel and now I want to run wire from the switch 60 feet inside the house and hook up to an outlet (30 amp) that will be attached to an exterier wall of the house. I have purchase a rain tight outlet box, the only thing I need to do is run the wire into the back of it from the basement.
> The question is, I purchased 10/3 NM-B with ground wire, the wire has a white, black, red, and un-cased ground. Would this be the correct wire to use? I had the impression that I needed 10/4 wire, with the ground wire cased,(green) but the Home Depot person stated that since this is an interior installation, that the 10/3 is what I need. Is the 10/3 wire correct? The transfer swich has a red, black, white and green wire to hook to.
> 
> Thanks for any help.
> ...


 Yes your fine ... ( but with this ... i have heard .. never happened to me .. that there are some inspectors get a bug up thier butt and want the 6 inches of wire that goes outside to be water tight ...)


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## Philly Master (Mar 30, 2013)

coldfrigman said:


> I read this post. My question is similar. I had to run a 68 ft length of 10/3 plus ground romex from the transfer switch to the inlet box in my garage. From there I have to use a 20 ft length of 30 amp, 10/3 cable to the generator. My generator is rated 7500Watts. Can I safely power my 10 circuits from my generator power switch, with this run and thickness of wire? I would only be powering 15 and 20 amp single pole circuits, like furnace, lights, frig, etc. I know about the 3 volts max voltage drop. I am confused when reading the voltage, watts, on line calculators. Thanks for any help.



I would never install an "inlet" *inside* a garage ..


besides that you should be fine ...


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## coldfrigman (Nov 14, 2013)

*what size wire*

I installed the inlet box, in a recessed way "tunnel" between two bump outs boxed with sheet rock. That way it can not be bumped or hit. It is about 10 ft from my garage door. Now I can attach a 20 ft 30 amp cord to connect to the generator outside. I was told in our town, we can do our own wiring, but have to obtain a permit, and get an inspection. So it seems, all are on board with me already using my 10/3 wire, and not to worry about voltage drop? does anyone think the inspector won't go for it, if they go by NEC as I am told? I really don't want to go through the added expense of using 8/3 wire, if I don't have to. The house is natural gas heat and gas stove, sewer, no well pump. Like I said frig, lights , furnace, microwave. Does the inspector take into consideration, what I am trying to power up? Thanks for all the help.


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## k_buz (Mar 22, 2012)

coldfrigman said:


> From there I have to use a 20 ft length of 30 amp, 10/3 cable to the generator.


I hope you mean 10/4...3 conductors + ground.


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## coldfrigman (Nov 14, 2013)

*wiring*

I used Romex brand NM-B 10/3 plus copper ground wire. I have a red, black, white insulated leads, and 1 uninsulated ground wire.


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## k_buz (Mar 22, 2012)

What did you use to connect the generator to the inlet?


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## coldfrigman (Nov 14, 2013)

Reliance 10/3 plus ground, 30 amp rated, 20 ft cord.


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## Glennsparky (Nov 30, 2011)

coldfrigman said:


> ... Does the inspector take into consideration, what I am trying to power up?


No. VD specs are just a recommendation and not enforceable. And you're within spec anyway. It's a non-issue.


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## coldfrigman (Nov 14, 2013)

You don't have a problem installing the inlet box in the garage , do you?
It is in a recessed location as I explained. Some homes have their breaker panels installed in garages anyways....


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## Glennsparky (Nov 30, 2011)

coldfrigman said:


> You don't have a problem installing the inlet box in the garage , do you?


There's a problem with carbon monoxide(co) sources too near a garage door, even if outside.

Houses often have negative air pressure. For instance, hot house air rises and is replaced by cold garage air. Co is drawn into the garage from under and around the garage door. Then the co is drawn into the house, killing the occupants. 

You have to be very careful who you kill. It could have repercussions.:whistling2:


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## coldfrigman (Nov 14, 2013)

*using staples on a perpendicular run for romex*

as far as running the romex 8/3 wire in the basement. Am I allowed per NEC code, to run the wires perpendicular to ceiling joists , using staples to secure the wires on each lip of joist? This is an unfinished basement ,furnace room area. I don't want to drill each joist, if I don't have too, but want to be assured of passing an inspection for electrical, by my town. If I have to drill holes, can I run (2) sets of romex wire, in the same holes?


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## Caleb (Jan 31, 2012)

coldfrigman said:


> as far as running the romex 8/3 wire in the basement. Am I allowed per NEC code, to run the wires perpendicular to ceiling joists , using staples to secure the wires on each lip of joist? This is an unfinished basement ,furnace room area. I don't want to drill each joist, if I don't have too, but want to be assured of passing an inspection for electrical, by my town. If I have to drill holes, can I run (2) sets of romex wire, in the same holes?


Just staple it to the joist, as long as you know it won't ever be moved. And you can run 2 wires in the same hole as long as it is big enough, no issue.


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## coldfrigman (Nov 14, 2013)

Okay, so it is code to do so, even if wires are not parallel but perpendicular?


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## Caleb (Jan 31, 2012)

As long as its protected from physical damage and is supported every 3 ft or so then it is code, I don't have my book right here so I don't know the support lengths exactly.


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## coldfrigman (Nov 14, 2013)

don't mean to be stupid, but what does "protected" mean? these would be just stapled to the lip of each board. I would put a staple on each joist.


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## Caleb (Jan 31, 2012)

It just means a place where it is subject to damage, should be fine.

Try to keep it as close to a wall as you can though


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## coldfrigman (Nov 14, 2013)

*Reliance control transfer switch*

I am planning on using a Reliance transfer switch 10 circuit unit for my generator in emergencies. It uses "mini" breakers for each of the 10 circuits. They are UL listed, and code. I would be powering only essential things like gas furnace, lights, frig. Does anyone have any concerns using this type of breaker as opposed to a full size breaker unit? The unit seems to get mostly excellent reviews. Thanks for all the help.


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## Philly Master (Mar 30, 2013)

QTElectric said:


> Just staple it to the joist, as long as you know it won't ever be moved. And you can run 2 wires in the same hole as long as it is big enough, no issue.





QTElectric said:


> As long as its protected from physical damage and is supported every 3 ft or so then it is code, I don't have my book right here so I don't know the support lengths exactly.



you cannot run it perpendicual to the floor joists UNLESS it is right up against the wall ....


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## Philly Master (Mar 30, 2013)

coldfrigman said:


> I am planning on using a Reliance transfer switch 10 circuit unit for my generator in emergencies. It uses "mini" breakers for each of the 10 circuits. They are UL listed, and code. I would be powering only essential things like gas furnace, lights, frig. Does anyone have any concerns using this type of breaker as opposed to a full size breaker unit? The unit seems to get mostly excellent reviews. Thanks for all the help.



the Reliance switch comes with breakers and that is what your stuck with ... no interchangability ...

http://www.homedepot.com/p/Reliance...i_kw=&ci_gpa=pla&ci_src=17588969#.UoyhuoU4m1A


now what we like is the Generac one because you can swoop out the breaker to fit your needs ... alll 15's all 20's etc etc etc ....2 poles etc... and then you can also use minis to get more circuits ...


regular siemens breakers


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## Caleb (Jan 31, 2012)

Philly Master said:


> you cannot run it perpendicual to the floor joists UNLESS it is right up against the wall ....


I have always been told by inspectors in my area as long as it is 8/3 and larger you can staple perpendicular, but they like to see running boards. For smaller wires, I'd bang some holes, its faster IMO.


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## Philly Master (Mar 30, 2013)

I should have took a picture yesterday we are "cleaning up" a job ..LOL 

2 unit apt. and landlord panel "ALL" wires neatly stapled to the floor joists individually perpendicular to the floor joists ..down the center..less than 7' high . about 40 running across basement ...about 4' wide ..LOL


the "protection" is subjective to the inspector ...LOL


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## Caleb (Jan 31, 2012)

Ah that is rough haha, around here they aren't picky about it at all, not sure why, as long as you have a running board they let it slide.


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## Philly Master (Mar 30, 2013)

No running boards ... Just 4' wide across the joists....lol each wire about 1.5" apart 30/40 wires


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