don716

Does anyone know how many amps a standard 8' shop light will pull? I'm running 3 8ft lights and 1 outlet on this.I'm thinking about adding more outlets even though I will probally be using only one at a time. Would there be a problem with a total of 6 outlets and 3 shoplights on (1) 20amp breaker?

Donny

Geoguy

Probably not recommended in a shop. Although, I've seen a lot worse that that without any negative effect but the potential is there. If you say you won't likely use more than one outlet at a time - that's probably true; however, the potential for someone to load 'em all up someday is still there. If it's wired correctly, it should throw a breaker in that event, but it's still not recommended. When I wired my shop, I put in a lot of circuits - no more than two outlets per run. Maybe that's a little conservative, but it passed the inspector.

By the way, the shop lights don't pull much amperage, sorry-don't know how much.

lucas.j.dunton

Put all of your shop lights on on 15 amp circuit wired with 14 ga wire by themselves. If not then whenever you start up a tool the lights are gonna dim and flicker from the initial start up drain. I would run one 20 amp GFI protected circuit for all of your outlets(12 ga wire), and then a dedicated circuit for any high powered tools (table saw, band saw, lathe, DC, etc). This will keep everything running smooth and will prevent you from overloading your circuits. At the least separate your lights from the outlets, or it will drive you crazy.

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mmwood_1

I absolutely agree. Besides that, if you are working at night and you trip a breaker, you do not want to be stumbling around your shop in the dark to get to the service panel, then have to find the correct breaker in the dark. Honestly, having once been walloped by a 440 circuit, the very thought of reaching into a breaker box in the dark gives me shudders!

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John in Tennessee

Anything that can run 220 make sure they are. Also as a card
carrying member of the ole fart society. Go over on the lighting. As you get older the eyes tend to go south on you. It will be money well spent. Not to mention you may want to rearrange your shop. I just had to move my compressor. My wiring expert knew I wasn't that bright and made it easy to move the plugs.

joasis

If you want to be exact, add the wattage of the bulbs (40 watts each, I would guess) for 80 watts total. Divide this by 115 and you will have the load per fixture of about .7 amps each...round up to take care of the electrical loss from the ballast and say an amp each. 3 fixtures will take a total of 3 amps...leaving 17 for the outlets. For simple expansion of the number of outlets, this will not be an issue....typically, in new construction, we have 4 outlets per breaker.....and don't run a 20 amp load on this circuit, like a planer or table saw, both potentially high load machines. Higher loads like these and other high draw items should have a dedicated circuit.

For those interested, Ohms Law.....:

P (power, expressed in watts)
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(amps) I * E (voltage)

If you know the amps and voltage, multiply for the power used....if you know the power, divide by the voltage to find the amp draw.

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smitty1967

Finally, a factual answer to a serious question! Hooray for Joasis!!

With all due respect and regard to the card carrying members of the Old Fart's society, spewing recitations of the way it's been done for years in your shop or the local watering hole or the church to which you belong don't give Donny the answer to his question (which was "How many amps...")

Donny: without going through the pain and expense of rewiring everything, try this...Use joasis' formula, and compute for yourself your amperage draw on that breaker. Then if you want to conveniently (but safely) add a receptacle or two, the math says that a 15A breaker should more than adequately handle it. This doesn't mean to string an extension cord and zip-tie it to the rafters....you have to maintain a 'best practice' attitude of doing things. Buy a small coil of romex, a few boxes and receptacles, drop the breaker to make the tie-ins...but by all means call in professional help if you don't feel comfortable.

good luck
smitty

Leo G

The lamps, if standard are usually 40 watts per bulb, usually 2 bulbs per unit so 80 watts per light. On a 20 amp circuit you can have 30, 80 watt light fixtures. That will draw 20 amps. Of course, you shouldn't do this. Also, I would put the lights on 2 separated circuits. So if you do trip a breaker 1/2 your lights will still be on.

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Gerry KIERNAN

Definitely what leo G said. Seperate your lights so that there is lighting on two [or more] seperate circuits. Even though you can run a lot of fluorescent lights on one circuit it is annoying if they all go out at once. And, as many have already pointed out, don't put any big loads on the lighting circuits or you will encounter dimming when the load comes on.

Gerry

jraksdhs

The NEC says you can have many outlets on a single circuit as you wish, i.e 2 or 50. The reason being is that you just as easily overload 1 as you can 10 at the same time. As far as lights go, I'd stay away from putting lights and outlets on the same circuit. I run 6 eight foot flourescent lights on 1 20 amp circuit and it only draws about 13 or 14 amps. I also dont have any 14 g wire either, its all 12g. If you have anymore questions feel free to ask?

jraksdhs

If your panel cover was on then that would have not been an issue......


Honestly, having once been walloped by a 440 circuit, the very thought of reaching into a breaker box in the dark gives me shudders![/quote]

woodnthings

The original post was back in 8 of 2008, This matter is probably all said and done by now and all the good advice given is probably too late for this question. Just thought I'd mention that. bill

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bzbatl

Not that it changes the estimated amperage pull that much - but with all due respect, typical 8' fluorescent bulbs are 60W, not 40W. It makes a minor difference in the calculation, but not much. You might be able to find 40W T8s in 8' length, but that's not typical.

4' will typically be 40W, although you can also get those in 30W depending on the bulb size, Kelvin temp, etc.

2' will typically be 15W.

*shrug* Lots of fish tank experience.

I have a question that kind of relates to this, though. I am almost done building out my garage workshop, and I don't have any additional spots in my breaker box to run a new line.

Instead of getting an electrician to install a sub - I was thinking about just running an EXTERIOR outlet inside. In other words, on the outside of the house (over the siding) I have an exterior GFCI outlet that is on its own 15a breaker (weird, I know). It is located in a spot that I absolutely never use. My thought is to take off the box, drill a hole to the inside of the garage, and run flexible shielded wire to the right side of my shop (which has no outlets).

Anyone see any issue with the GFCI plug interfering? I'd like to leave it out there just in case one day I actually do use it (however unlikely it seems right now, I'm sure I'll need it the day after I remove it).

dollis

I have wired 10-12 shops from 12,x12' to a 120'x80' In everyone i have used a minimum of 2 breakers for lighting. The first time you stand on a 12' ladder in the dark to replace a ballast or even a light bulb you will start using 2 breakers! Outlets in a shop should be "IMHO" what are called small appliance circuits (2 duplex outlets). Seems like overkill OK, having lived in the south before being dragged to Yankee land. Everyone need's a fan (or now heater) near them + a router 1 hp router draws ~18A so their is you breaker load. Don'T use a router fine, heater + hand drill or table saw you may the capabilities some day wire the shop right once.

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moondawg

You can do that. Just remember that if the outlet on the INSIDE is dead, that you might have to go OUTSIDE to reset the GFCI.

Also remember that when you FORGET that the circuit passes through that outside GFCI, it will drive you BATTY trying to figure out why your outlet is dead. :^)

jraksdhs

1hp router drawing 18 amps? A 3 1/4 porter cable router draws only 15 amps on start up and runs around 12 at max.....

bzbatl

You know, at one point I had remembered that, but forgotten when I posted. Thanks for reminding me

I think that may end up ticking me off more than it's worth. Worst part of the plan will be repairing that Hardi siding where the hole was cut for the outlet...

Understandably, it will not be up to code if I swap out that GFCI outside with a regular... but is there any real danger to that plan if I never use it anyway? I'll just have to remember to swap it back out when I sell the house.

GeorgeC

You are correct. A 1hp anything electric (router, saw, jointer, etc.) will draw about 7 to 9 amps from a 110 volt circuit, depending upon motor efficiency.

George