Wiring for a compressor in attached garage

[OhCookie]

Hello, my husband and I are trying to understand the scope and figure out the cost of getting our Sanborn 5HP, 175 psi, 2-stage compressor wired into the attached garage. It doesn't look like there is any room left in the main panel, which happens to be less than 15 ft from the garage. We will consult and hire a licensed electrician but we would like to get an idea of what our options might be. We aren't opposed to a sub-panel if that is an option. We live in a townhome in California.

I have included photos of the main panel and the first floor layout.

Looking for any advice, guidance, opinions, etc. Thanks!

Front of main panel:


Inside of main panel:


Layout of first floor:


The compressor:

 

[JJThrasher]

Yep your panel looks full. From the plan it looks like your dyer shares a wall with the garage. I wonder if that circuit could be expanded.

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[pattenp]

Your panel looks like it is a sub panel. Where is the meter and main disconnect located that serves that panel?

 

[OhCookie]

Your panel looks like it is a sub panel. Where is the meter and main disconnect located that serves that panel?

There are 8 units to each building, and each one has a small closet for electrical, phone, cable, etc. Maybe that is where the main panel is located.

 

[OhCookie]

Yep your panel looks full. From the plan it looks like your dyer shares a wall with the garage. I wonder if that circuit could be expanded.

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We were wondering about that too.

 

[e-tek]

If that's a multi unit building did you check that you're ok to install a compressor outside your unit?

 

[OhCookie]

If that's a multi unit building did you check that you're ok to install a compressor outside your unit?

Negative on the compressor going outside. It must be kept in the garage.

 

[Aceman]

That panel is stuffed. I can see only one breaker in the lower left that isn't twinned up like the rest. If you can replace that with a twin that would give you a single 20 amp 120v circuit you could use. But that won't cut it for that big 5hp you have, that needs 240v.

So, I'd say if you want to run a compressor, you need to pick up a smaller 120v unit.

They wire apartments as cheap as possible usually, low bidder wins. Unfortunately, they used the smallest panel possible in your case.

 

[OhCookie]

That panel is stuffed. I can see only one breaker in the lower left that isn't twinned up like the rest. If you can replace that with a twin that would give you a single 20 amp 120v circuit you could use. But that won't cut it for that big 5hp you have, that needs 240v.

So, I'd say if you want to run a compressor, you need to pick up a smaller 120v unit.

They wire apartments as cheap as possible usually, low bidder wins. Unfortunately, they used the smallest panel possible in your case.

What about the upper right of the panel? The top right breaker is for the garbage disposal unit and nook lights (which are used infrequently). Can anything be done with those? Can anything be run off of this panel?

 

[RickP]

What about the upper right of the panel? The top right breaker is for the garbage disposal unit and nook lights (which are used infrequently). Can anything be done with those? Can anything be run off of this panel?

You could use those two breaker slots, but you'd have to pull the current breakers out completely. Then you could use that space to feed a subpanel next to your current panel. But all four of those multi-wire branch circuits would have to be moved to the subpanel. If you decide to go this route, it might be easier to use the two slots on the lower right, because then you'd only need to move two regular circuits.

The materials to add the subpanel would probably be under $200, but I don't know how much labor would be involved. Talk to your electrician -- it might be better to replace the whole panel, especially if you used the same brand (Eaton) so you could re-use the breakers. I just bought a panel box from Eaton and they are pretty reasonable. The cost of that might be about the same as adding a subpanel -- slightly less in materials and a little more in labor.

As far as the wire run to the garage, it's not a long distance, so the materials are not going to cost that much. Maybe $2 per foot for the cable, plus $15 for a new breaker. (Don't forget to measure the distance up into the ceiling and back down to the compressor.) The real cost is going to be the labor to pull the wire through the ceiling and walls. You might be able to save a little by pulling the wire yourselves.

 

[OhCookie]

You could use those two breaker slots, but you'd have to pull the current breakers out completely. Then you could use that space to feed a subpanel next to your current panel. But all four of those multi-wire branch circuits would have to be moved to the subpanel. If you decide to go this route, it might be easier to use the two slots on the lower right, because then you'd only need to move two regular circuits.

The materials to add the subpanel would probably be under $200, but I don't know how much labor would be involved. Talk to your electrician -- it might be better to replace the whole panel, especially if you used the same brand (Eaton) so you could re-use the breakers. I just bought a panel box from Eaton and they are pretty reasonable. The cost of that might be about the same as adding a subpanel -- slightly less in materials and a little more in labor.

As far as the wire run to the garage, it's not a long distance, so the materials are not going to cost that much. Maybe $2 per foot for the cable, plus $15 for a new breaker. (Don't forget to measure the distance up into the ceiling and back down to the compressor.) The real cost is going to be the labor to pull the wire through the ceiling and walls. You might be able to save a little by pulling the wire yourselves.

Now that sounds feasible. Thanks RickP!

 

[pattenp]

I'm still wondering where's the main disconnect that's feeding that panel. Can another sub panel be added from the main disconnect panel.

 

[RickP]

I'm still wondering where's the main disconnect that's feeding that panel. Can another sub panel be added from the main disconnect panel.

That would be the cheapest and easiest solution if the electrical closet is near the garage, or has a conduit run to the panel inside the house. Where's the meter?

 

[OhCookie]

The meter is in the utility closet at the end of the building. It's a townhome not an apartment building, and there are 8 units to each building. The utility closet is exactly two units over from me.

 

[RickP]

The meter is in the utility closet at the end of the building. It's a townhome not an apartment building, and there are 8 units to each building. The utility closet is exactly two units over from me.

Depending on how the electrical panel is set up in that utility cloest, it might be easier for you to add the compressor circuit breaker there, rather than changing the panel in your townhome. Is there conduit running from there to your panel? If not, you'd need your neighbors permission to run a cable through their attics -- that's probably the toughest part right there.

 

[OhCookie]

Depending on how the electrical panel is set up in that utility cloest, it might be easier for you to add the compressor circuit breaker there, rather than changing the panel in your townhome. Is there conduit running from there to your panel? If not, you'd need your neighbors permission to run a cable through their attics -- that's probably the toughest part right there.

The HOA will not allow me to do anything like that. I can do what I want inside my townhome, but I cannot add anything to that utility closet, nor can I run anything through my neighbors attics.

So, is upgrading the existing panel, which I assume is really a sub-panel, the only real option I have?

 

[pattenp]

Do you know what the service size is to your townhouse? You need to see what size the main disconnect breaker is to your townhouse. It should be located at the meter. Also is the service wire to your panel in the townhouse copper or aluminum and can use see the AWG size printed on it?

 

[OhCookie]

pattenp, I will have to check when I get home. I'll post up my answers later.

 

[pattenp]

This is kind of a crappy way to get more space but you can use the existing panel as a junction box to extend a few of the existing circuits to a second panel like the one you have just below the existing panel. The circuits to be relocated will be passed through the old panel going out the bottom knockouts then into the new panel below. That will free up space in the old panel to put in the feeder breaker to supply the new panel. Is that clear as mud?

 

[OhCookie]

Yes, I get it. Thank you for all of your advice and insight. I told my husband this is the site to go to for questions like this.

 

[Keyrick]

Cookie, If I may ask, what kind of work are you going to do in your townhouse garage that would require a 5 HP, 175 PSI compressor? It looks like it is a 60 or 80 gallon unit. Don't get me wrong, you can do whatever you want to do, but a unit that size can power lifts and air tools at a small gas station. The reason I ask is that by the time you get an electrician out to put in a sub-panel and wire it up, It may be cheaper to get a small 2 or 3 HP 30gallon unit that runs on 120 volt from HD or Sears that will provide you with the amount of air that you need. That big boy will be loud as well, where the smaller unit would be quite a bit quieter. Just asking.

 

[OhCookie]

Keyrick, it would be for media blasting and my husband's air tools and other projects. We already have a 13 gal. that we have had for years, but decided to go bigger. It was the right price so we could not pass it up.