running 230v for compressor

[Roch_Greg]

I'm want to be able to put in a larger compressor (looking at the Belaire 318VN from Len) in my detached garage. I rent the home not own so putting in a sub panel or changing anything in the main one is out of the question.

There are two double pole breakers in the main panel. One of the Central AC (hardwired) and one for the Electric Range. I have a gas dryer so no 230 lovin there. So it looks like the Electric Range is the only one open to me.

Now here is where I am confused. I know I can run an extension cord from the receptcal to the garage (yes I know to watch the wire gauge for voltage drop) but the compressor is rated at 22 FLA whereas the the breaker at the panel is 40 amps.

I'm thinking that a 40 amp breaker on a 22 amp circuit is too big, it'll never "pop" when it's supposed to. So how can I get a 30 amp breaker in-line or at the garage end of the line.

Second question. The new NEC wiring code calls for all 220/230/240 receptacle's to have 2 hots. a neutral, and a ground. That's how the one is for my Range. The compressor I'm imagining won't use the neutral and just have two hot's and a ground.

So would I need a three or two wire configuration for this project.

TIA

Greg

[JDHolmes]

Greg, why not just pop in a new 30 amp breaker in the panel and wire it to the compressor? Actually, even a 30 amp breaker won't pop on the compressor. Since the fla of the compressor is 22 amps, it'll probably burn up before it pops a 30 anyway.

Depending upon how your panel is set up, you could wire up a heavy duty rubber coated wire (quite expensive) directly from breaker to compressor, with some extra slack for moving the compressor around a bit. You pop in the breaker, make sure you can get out the side of the breaker panel. Use a 3/8 or 1/2 connector in the side of the panel to make sure moving the cable doesn't pull it out of the breaker.

I actually went through the upper sill plate with 3/4 wood bit, dropped a string to box and pulled new wire through the ceiling of the garage to where I wanted it to be. This only works on non-insulated garages however.

If your garage is insulated, cut out a hole for an old work box near the floor, run a wire up to the panel and pull the cable down to the box and out. As a cover, use a cable tv cover but drill out the hole to accomodate your wire size. You can also use a metal cover and cgb for additional strength and not pulling it all out of the sheetrock/wall.

NOTE: Make sure main panel power is off when you do this unless you are an electrician or have done this work before. More people die of 120 volt accidents than any other type of electrical incident.

Also note that your main service may not be able to handle an additional amp draw and may blow main breaker or others

[CDJr]

Greg, the breaker isnt there to protect whats plugged into an outlet, its there to keep an excessive amount of current from being transferred through the wire on that circuit, which, if overloaded, would overheat and could cause a fire. Think of it as being similar to a governor or a rev limiter. The fact that its a 40A breaker is actually good, as it means that circuit should have wire capable of carrying a heavy current, in your case, enough to operate an electric oven. However, unless you no longer use the oven, youre gonna need to take anouther route. That is a dedicated circuit for the oven and isnt capable of carrying enough current for both. Youll probably need to add a seperate circuit and feed from the main directly to the compressor using a new breaker and new wire. That way, while youre outside using your compressor, your wife will still be able to have dinner ready for ya when youre through :D

[teetop60]

Hey Greg,
I had an local independent electrician wire my 220 for fifty bucks. It took him about 15 minutes and the price included all the materials and a 220 plug in box. I thought about doing it myself but electrical work that requires hooking into the main box can be dangerous. Besides that, the materials needed would have cost me about 20 bucks. While he was there I had him put in a lightning arrester for another 50. You might want to check out out some local electricians before embarking on a potentially dangerous DIY mission.
Teetop60

[Roch_Greg]

Thanks guys for all the intuitive answers but I think we are not all on the same page.

I "CANNOT" modify the existing panel under any circumstances. This would include

1) Adding breakers to the panel
2) Changing the size of an exiting breaker

Remember I stated I rent the house not own it.

Anyway this is not a permenate solution in that I want the compressor wiried up all the time, if such were the case then I would be looking for a different solution. I'll have to switch between the two (range and compressor). Since I'm single and live alone that won't be a probelm as there is no one else using the range if I'm not.

I've researched my idea and talked it over with the electrians at the plant. I'm just going to run some 10/3 or 10/2 out to the garage.

The end in the kitchen will have the same plug on it as the range to match the receptecale. The end in the garage will terminate in a safety switch box with a 30 amp fuse (so if it trips I don't have to walk back to the house panel). I'll then wire the pressure switch (some Belaire's don't use a mag starter) to the safety switch box.

[CDJr]

Ahhh, I see what youre sayin Greg. And it sounds like your plan will work fine ;)

[Roch_Greg]

Thanks CDjr, I'm glad I could clear up any ambiguity. It's certainly going to be a PITA esp working with 10 qauge wire (it's so heavy).

But I gotta tell ya, not having enough air supply and waiting for the tank to re-fill is even more of time waster.

[Ranchero_65]

Greg, Do you have a dryer ? it's more than likely 220 ..

[55chevrolet]

Greg you seem to think that a 230/240 compressor won't need anything but 2 hots and a ground. Be aware the control curcuit going thru your pressure valve that starts and stops the motor is undoubtably 110/120 and WILL need a ground as well as a nuetral.

That is why the code says to have a 4 wire hook up. The motor may not need a 4-wire, but for your safety, the contorl curcuit does

[Roch_Greg]

Ranchero_65:

I listed my Gas dryer as running off 115 (only has a single pole 20 amp breaker)

55chevrolet:

I stated I was going to pull 10/3 which is a 4 - wire cord I which beleive has (2 - hots, 1 - ground, 1 - neutral).

The electrican at work said I might be able to use 10/2 ( 2 - hots, 1 - neutral) to make the wire a little more manageable (and cheaper as copper has gone thorugh the roof) but I'm undecided on that.

In any case I doubt I need 10/4 (3 -hots, 1 - gnd, 1 - neutral).

I already own a Belaire Compressor and have spoken with their Sales and Tech support on occasion before.

They seem friendly and knowledgeable enough so I'll be sure to ask them what type of wire I would need to hardwire the compressor w/out a mag starter.

Maybe even Len knows as he has worked with the product line before.

Thanks fellas for all the input, I like to get things right the first time and your helping me to think of all the angles.

Greg

[Ranchero_65]

Sorry Greg I missed the dryer part when reading post.. :rolleyes:

[Roch_Greg]

It's no biggie. everyone is trying to help, that's the important part.

[mdbrandy]

Greg you seem to think that a 230/240 compressor won't need anything but 2 hots and a ground. Be aware the control curcuit going thru your pressure valve that starts and stops the motor is undoubtably 110/120 and WILL need a ground as well as a nuetral.

That is why the code says to have a 4 wire hook up. The motor may not need a 4-wire, but for your safety, the contorl curcuit does

I just installed a 220V Porter Cable Compressor, and could find no use for the neutral. There was no place in the compressor's connections for use of the neutral - just 2 hots and a ground. No other connections available, motor or control. There is no mention in the manual for the compressor about needing 120/240 power. So from what I can see, your statement will not always be true. If you can see where I might have gone wrong, I'd be very happy to hear where, since if you're right, it would be a safety issue, since the ground would then have to carry neutral current. I don't believe that is happening, though and the compressor runs fine. It's a Porter Cable C7550 BTW.

Thanks.

Mark