Electrical hook up for new compressor.

[JBRES1]

I pulled the cover off of my fuse box today and found that I don't have a ground block on my board.( My office/warehouse building was built in 1981.
The fuse box is a GE load center and rated for 125 amps.
The compressor is a 220vac/1/60 Airetex W31 unit.
I am running a 1/2" conduit and using 10 ga. wire , and a 220vac outlet , and a 30 amp fuse.
Where would you connect the ground wire in the box, would you use one of the mounting screws to attach it to ?
Thanks, JIm Breslin

 

[spectrum]

There should be some sort of bare ground wire going to a bussbar to service all of the other earth grounds, just go there. This may be the same bar as the neutral (white) wires.

In the outlet box you also want to bond the box. It's easiest to strip the wire extra long and to detour to a ground screw that will go into the tapped hole in the box. Then continue on to the ground terminal on the outlet. This way if the outlet is removed from the bx while energized the box will remain grounded in case there is a fault.

Pete

 

[do it easy]

Let me know if you want some tanks for "test" fills. I can supply them on a regular basis.

 

[firemedic1015]

A building built in that vintage probably does not have a "floating neutral" bar in it. Which means that all of the grounds and neutrals will be connected on one terminal bar. Look for the terminal bar where all of the white, green or bare copper wires are and attach it there. If your compressor has a four wire cord on it, both the white and green wires would be attached in the same place on the panel. Of course if this doesnt make any sense to you, you should consult a qualified electrician to give you guidance.

 

[Teamcasa]

Is the compressor a three wire plug? Most likely it is. Connect the white/netural to the buss bar where all the other netural are. Then again taking electrical advice from a scuba forum, you get what you pay for. As Firemedic said, Call a qualified electrician.

 

[rjack321]

I pulled the cover off of my fuse box today and found that I don't have a ground block on my board.( My office/warehouse building was built in 1981.
The fuse box is a GE load center and rated for 125 amps.
The compressor is a 220vac/1/60 Airetex W31 unit.
I am running a 1/2" conduit and using 10 ga. wire , and a 220vac outlet , and a 30 amp fuse.
Where would you connect the ground wire in the box, would you use one of the mounting screws to attach it to ?
Thanks, JIm Breslin

My Alkins W31 has a 3 wire motor, not 4. So you have 2 hots and a neutral. No green "ground" per se. Just connect the neutral with all the other white and bare copper leads inside the panel. I would definately not use any of the case screws of the box to attach the neutral lead.

I also used 10ga wire, to wire my subpanel which is also 30amps. But 1/2" conduit might be too small to dissipate heat. I'm not an electrician but I recall that being marginal. I have 3/4" Sch 80 conduit.

 

[spectrum]

Is the compressor a three wire plug? Most likely it is. Connect the white/netural to the buss bar where all the other netural are. Then again taking electrical advice from a scuba forum, you get what you pay for. As Firemedic said, Call a qualified electrician.

Whoa!
The OP said:
The compressor is a 220vac/1/60

That means 2 hot wires and an earth ground, no neutral.

Since he is running conduit and I assume pulling independent conductors there should be 2 hot wires that can be anything BUT green or white, they can be the same color. These will each go to a fuse pair from opposing phases. Or on a pull-out. Although he repeats the term fuse I have to believe that in that vintage they are actually breakers. A double pole breaker will by design connect to a pair of phases wherever it is inserted. (no 1/2 size cheater breakers here)

A green wire will also be pulled for the earth ground. This will bond all metal including the outlet and box. It will terminate to the ground/neutral buss in the panel where all of the other bare wires and white wires from 110VAC circuits are grouped.

If he is pulling Romex into the conduit he will have a black, white and bare. The black and white will be used as hot wires and the bare will be the earth ground. Since the white wire is not being used as a neutral it should be somewhat wrapped with electrical tape of a color other than white or green.

In no case I can think of should he be connecting a white wire to the panel neutral/ground buss.

As others have said if this is not making sense get an electrician or handy buddy.

Pete

 

[underboats]

Jim,
That unit has a three wire hook-up. With the wire size you are using 1/2 conduit is fine unless you are making a very long run. That unit, other than startng does not draw much of a load. In your box you will have a buss bar with the neutrals and chassis grounds. All you will hook up is the two hot wires to the breaker and then the ground to the buss bar in the box. As others have said this is the buss with the white and bare ground wires connected to it, your box will have this buss. You can add a chassis ground which would be the fourth wire but it's not necessary if you have a standard hook-up and a good location for the compressor. If it's outside than maybe you would want it but again it's not necessary for most uses. IM back if you want more information.

Chuck

 

[JBRES1]

Thank you all for responding.
1) yes it is a 30 amp double pole breaker. Showing my age calling it a fuse.
2) The run will be 30 ft. of wire , 10 ga.
3) Tony stop by and I'll be happy to give you a test fill. But I may put you to work
hauling storage tanks around.
4) I took some pics of the breaker box and am going to see an electrician at one of
my customers on Monday. He has offered to help me out, and do the install if I'm not comfortable with it.

Thanks, Jim B

 

[spectrum]

T
3) Tony stop by and I'll be happy to give you a test fill. But I may put you to work
hauling storage tanks around.

Are you saying you have banks too?