Electrical questions...

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Crashmph

Crashmph

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Joined
Dec 15, 2008
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South Riding, VA
Hi all,

I am wiring in my entire garage for my new subpanel... relax, it is not even connected on the other end to the main, nor will I be connecting it. I will pay a licensed electrician to do the work I feel unqualified to do. Then the county will stop by for the required permit inspection. Yes I did get a permit.

I have 12 four foot dual bulb electric ballast lights in a 4x3 pattern of my shop. They have a amp rating of 0.8 Amps per light which gives me an overall amperage of 9.6 Amps. Can I put all of these lights together on one single 15 Amp circuit and 15 Amp switch, or should I put it on a 20 Amp circuit and 20 Amp switch? I think it should be a 15 Amp circuit and switch.

Also, for all of my outlets along the walls, are they required to have a 8-12" drop down the wall from the lateral run of the supply wire from the panel?

Thanks for any help and advice.

Michael
 
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I have similar lighting set up, they are all on theor own 20a breaker. 15 is most likey fine, I guess the tiny bit more to "over do" it was worth it to me.
 
My biggest worry is making sure everything is to code for the inspector. I do not really want to have to give him/her an excuse to fail me on the inspection.
 
Call the code office and ask or ask the certified electrician who is somewhat helping you with the connection.
Do a good turn daily!
Don

Crashmph said:
My biggest worry is making sure everything is to code for the inspector. I do not really want to have to give him/her an excuse to fail me on the inspection.
Click to expand...
 
I have 16 2 bulb 8' high output electronic ballast flourescents in my shop all on the same switch with a 20 amp breaker. My electrician wired it all to code so I know it is right.

As for the drops...what code does your location use? Most likely the NEC but there are others. I am not 100% sure on shop wireing but on the homes that I build, it is not required to do the drops you are talking about.

I am not an electrician, just a builder so you might want to see what an electrician says to be sure.
 
Have you ran the wires for your lights yet? If you have the wire size will determine your amp breaker size. 15 amps will work for now but what about as the lights age and their efficiancy drops will increased load over do it? will you want to add more in the future? How about splitting your lighting loads on to 2 15 amp circuts leaving room for future use? Just dont put outlets on the same circut as the lights. I had my electrician run all 20amp circuts for all outlets and 15amp circuits for lighting when I built my house. Keeps the lights on when you trip a circut breaker from a load. It also helps to keep the lights from dimming when something with a load is plugged in and turned on.
 
F.Y.I. Just adding a bigger breaker does not make it safer. If you put it on too small gauge wire you are creating a fire hazard.

You have to make sure that you have the correct gauge wire for the 20amp circuit. Code requires min. 12ga wire for a 20 amp breaker. 14ga min. for a 15 amp breaker. If it is just the 4 lights at 9.6amps (which is full load, not working load) you are more than fine.

I not only stayed at a Holiday Inn Express, I was an electrician for many years.
 
If you run 12/2 w/grd wire for your lights, 12 guage is rated for 20amps so you could run a 20 amp breaker and switch. I always run 12/2 w/grd for all standard circuits and usually use a 15 amp switch depending on the load on the circuit. For safteys sake be sure it is up to your local code.

Good luck

I type to slow Rob already said that.
 
If you run a 20A circuit, you've already been told you need #12 wire. You may also need a 20A rated switch, depending on the inspector. I'd put one in, though I'd have to hunt a bit as most of the ones you'll find are rated 15A.
 
It's been said, but I would split it into two circuits.

When one goes off, you are not totally "in the dark" with a spinning blade in front of you, still working!!!
 
If you are on a 20a circuit you should always use a 20a rated switch or outlet. 15a rated switches and outlets will work on a 20a circuit, but can overheat and will be a fire hazard.
 
Crashmph said:
Hi all,

I am wiring in my entire garage for my new subpanel... relax, it is not even connected on the other end to the main, nor will I be connecting it. I will pay a licensed electrician to do the work I feel unqualified to do. Then the county will stop by for the required permit inspection. Yes I did get a permit.

I have 12 four foot dual bulb electric ballast lights in a 4x3 pattern of my shop. They have a amp rating of 0.8 Amps per light which gives me an overall amperage of 9.6 Amps. Can I put all of these lights together on one single 15 Amp circuit and 15 Amp switch, or should I put it on a 20 Amp circuit and 20 Amp switch? I think it should be a 15 Amp circuit and switch.

Also, for all of my outlets along the walls, are they required to have a 8-12" drop down the wall from the lateral run of the supply wire from the panel?

Thanks for any help and advice.

Michael
Click to expand...


Michael

You say you are having an electrician do some of the work. I would suggest asking him his professional opinion instead of getting the opinions here. I can tell you this it is to your advantage to use the #12 wire and a 20 amp circuit with a 20 amp rated switch for the lighting and my reasons are these, you have the capacity to add on in the future if need be., with electronic ballasts they are suspect to voltage drop and in the summer power compinies cut back on power supplys to conserve along with greater demand so voltage drops. You eliminate a factor with the larger wire if you are close to total amperage of the circuit. As far as switching goes you can break up the light pattern by adding more switches( this is how 15amp switches are used on a 20 amp circuit) to control less lights and still use one 20 amp circuit.

The outlets, I do not understand what you are asking so I would leave that one for the person who is looking at it. Remember this is a garage shop so the codes for a garage must be followed and again this is a job for your local electrician who should know the electrical codes and also the local codes which can differ. So be careful taking advice on the internet.

Just reread something here and one thing never put lights and power outlets on the same circuit.
 
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I am sorry, but you should never use a switch or outlet rated lower than the amp rating on the circuit breaker.

The NATIONAL ELECTRIC CODE STATES: all devices connected to a circuit shall have at least the same ampacity rating as the "overcurrent protection device" (circuit breaker) that supplies the circuit.

For John and the rest, that means you should not use a 15 amp switch on a 20 amp circuit.

As a ELECTRICIAN, I always run 12 gauge wire and then a 15 or 20 amp breaker.

And I won't insult your intellegence by warning you against taking advice off the net, and then giving you advice.

Just my 2 cents.
 
I am the light . . .

I am the light overkill guy . . . I have a 20'X22" shop with a 10' ceiling. I have (24) 2 bulb 4' fluorescents. Have them set up on three banks. Used 20 amp breaker, 12 gauge wire & 20 amp switches. They cost pennies more and last forever, although the 12 gauge wire will cost considerably.

DO NOT PUT ALL YOUR LIGHTS ON ONE SWITCH IF YOU HAVE A CHOICE. ! ! !

If you should loose that circuit for any reason while working in the shop at night you could find yourself in big trouble, especially if the table saw is still running and you are still cutting . . .

Besides there are times you will want to shift light on a project. I like ALL the light I have. When I did the the light calcs for the shop I had operating room standards at 36" from the floor.

Another thing that many will argue, low voltage to ballast reduces their life and increases their noise level. Smaller wire equals low votage. I have the same light fixtures, 6 of them on #14 in my garage and they are noticeably louder. These are all T-8s.

Steve
 
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