How many outlets per 20A breaker?

[weatherby460]

I am running about 20 wall outlets in my 30x40 shed. How many per breaker should I do, and what gauge wire? Thanks.

Nothing will be a dedicated outlet for any special type of equipment.

 

[weatherby460]

Also, do I need to use a GFCI?

 

[Jason280]

I ran 12/2 to all plugs, put no more than 4-5 on a 20a circuit, and used 20a receptacles in my shop build.

 

[2Big2Ride]

Disclaimer: I am not an electrician.

My understanding is in the USA there is not a limit on the quantity of recepticals installed in a circuit for residential applications. You may will find commonly stated recommendations for up to 12 or 13 recepticals on a 20A circuit.

If you run a 20A breaker you need at least 12awg wire. The answer may be different depending on the length of your wire run and how you are getting power to your shed, and what you do once the power is at shed.

Yes, need GFCI protection on the circuit for a garage or out building.

 

[justsam]

How does power get to the shed? Is there a subpanel there or are you talking of running individual circuits to an attached structure, which you can not do.

As stated you must use a GFCI. This can be a breaker or a GFCI receptacle at the head end of the branch circuit, using LINE/LOAD of the receptacle.

 

[HotwheelsYJ]

Use 12-2 wire. 1st outlet of each circuit is GFCI. I put no more than 8 on one circuit but there is no rule on that, only recommendations. It takes more wire but I alternated circuits on side by side outlets. I have single gang boxes on every other stud (16" stud spacing so 32") so if I'm working in a concentrated area I have access to 2 circuits.

 

[wyliesdiesels]

How does power get to the shed? Is there a subpanel there or are you talking of running individual circuits to an attached structure, which you can not do.

As stated you must use a GFCI. This can be a breaker or a GFCI receptacle at the head end of the branch circuit, using LINE/LOAD of the receptacle.

Im assuming u meant DETACHED structure, as attached structures can have individual branch circuits run to them.

 

[justsam]

Im assuming u meant DETACHED structure, as attached structures can have individual branch circuits run to them.

Thanks for catching my error.

I think my brain and typing fingers were detached!

 

[theoldwizard1]

There is no hard and fast limit in the NEC. If you are planing on an electronics work bench that might have a lot of low current equipment 10 or more duplex outlets or a power strip with a dozen or more outlet is not unreasonable.

It is also unlikely you are going to be using a large number of power tools simultaneously.

 

[soj]

Thanks for catching my error.

I think my brain and typing fingers were detached!

Time to re-attach 'em! Try wiring them up with individual branch circuits... I mean cups... of coffee.

 

[weatherby460]

How about fluorescent lights...how many of them can be on a breaker and do they need a gfci breaker?

 

[walrus]

How about fluorescent lights...how many of them can be on a breaker and do they need a gfci breaker?

Depends on breaker and amperage of lights. 16 amps of lights on 20 amp circuit, 12 amps on 15 amp circuit. Residential, lights in garage on GFCI in latest code, doesn't have to be a breaker could be load on a gfci recept.

 

[Norcal]

Depends on breaker and amperage of lights. 16 amps of lights on 20 amp circuit, 12 amps on 15 amp circuit. Residential, lights in garage on GFCI in latest code, doesn't have to be a breaker could be load on a gfci recept.

Only if cord and plug connected, hardwired, no.

 

[BAndritsch]

Way back when I was at a code update class we had this conversation with the inspector.
According to him at that time there was no limit to the number of receptacles on a branch circuit but this would be determined by the projected load. At the time we would use the accepted number of 10 per circuit. With the influx of electronics in homes that had to be rethought, in a home shop while the receptacles have to be GFCI protected the lighting doesn't as long as it's hard wired as stated by NorCal. I would go to the extra expense of using GFI breakers for your wall plugs, much easier to install and last longer than the receps. I would like to add from experience do not ever plug the wires into the backs of your outlets. This was brought about as a great timesaver during installation but really causes lots of grief down the road. I always wirenutted the circuits in each box with pigtails to the device on the screws. Dedicated outlets didn't have to be protected when I was still working. The thing is 1 man working in his garage usually won't have more than 1 piece of equipment running at a time with maybe the exception of a fan or something like that also. There are some great books available in the home centers to help you.
Bill

 

[Speedy Petey]

According to him at that time there was no limit to the number of receptacles on a branch circuit but this would be determined by the projected load.

Correct.

At the time we would use the accepted number of 10 per circuit. With the influx of electronics in homes that had to be rethought,

Makes no sense. Newer electronics are lowering the amount of power used for the respective device. Even with more devices, electronics really do not draw very much contrary to armchair electrician's thoughts.

I would go to the extra expense of using GFI breakers for your wall plugs, much easier to install and last longer than the receps.

The ease of installation between the two types of devices or breakers is a completely moot point. The differences are negligible.

Dedicated outlets didn't have to be protected when I was still working.

This was not exactly true, the exception was NOT for "dedicated outlets", but was for large appliances that blocked access to the receptacle, and for receptacles above a certain height. The exception is long gone and ALL 120V 15 & 20A receptacles in a garage need GFI protection.

 

[tarbellb]

The rule of thumb my electrician buddy told me (Denver CO) was 80% amp load of whatever breaker size you are using, given the correct wire size.

So 20 amp breaker = 16 total amp load


Also, with GFI I was also told that you really only need one GFI on a circuit, and to the first receptacle in line as it will trip for all the receptacles following it.

Speedy, you seem to have a handle on this. Any sense it what I was told?

 

[Speedy Petey]

The rule of thumb my electrician buddy told me (Denver CO) was 80% amp load of whatever breaker size you are using, given the correct wire size.

So 20 amp breaker = 16 total amp load


Also, with GFI I was also told that you really only need one GFI on a circuit, and to the first receptacle in line as it will trip for all the receptacles following it.

Speedy, you seem to have a handle on this. Any sense it what I was told?

The "80% rule" is ok for some things, but to put a blanket 80% rule for all circuits is silly IMO. Most circuits can be loaded to 100% quite often, just not continuously (per the NEC definition).
And for general use receptacle circuits it is nearly impossible to tell what the load is going to be, so to say to keep it to 80% is a meaningless thing. 80% of ten duplex receptacles is 8 duplex, or 16 receptacles. How much do 16 receptacles draw?

 

[tarbellb]

I agree with the number of receptacles not having a impact on the breaker size. I was giving a actual value on what should be considered when thinking about how they are being used.

What about the GFI as the first receptacles in line?

 

[Stuart in MN]

What about the GFI as the first receptacles in line?

That is perfectly acceptable. It's best if the GFCI is in an easily accessible location.

 

[Norcal]

That is perfectly acceptable. It's best if the GFCI is in an easily accessible location.

It's not "best", it is required to be accessible.

 

[weatherby460]

How many outlets downstream of the gfci?

 

[Stuart in MN]

How many outlets downstream of the gfci?

Again, for residential work there's no limit.