Electricians Out There?

[shanenin]

I am installing a central air unit. I have some help with the plumbing and rerigerant side of it. It is my job to install the electical box out side. This box consists of a couple of fuses, and a pullout switch. Here is where I am bumping heads with my helpers. They seem to think it is correct to connect both my ground(green) and my neutral(white) all together to the spot in the box, the place only the ground(green) is supposed to be connected. There rational is since the ground and neutral goto the same spot in the main elctrical box, it is ok. I know that is incorrect. Doing it the incorrect way like they reccomended, what problems could it cause.

I can if see doing it the wrong way, both my ground and neutral will be carrying current, is that nessesarily hazardess?

none the less, I won't do it incorrectly, but was looking for a way to explain to them why it should not be done that way

thanks for any input :-)

[jimras]

Hi Shanenin

MOST central air units are run off of 220 volt AC.

If that's the case, you sure don't want to be hooking two of the wires to the same terminal in the box. I'm no electrician but I know better than to try to rig up something like that. That green wire is supposed to be the GROUND connection and the white is the Nutral. I don't think you should combine them.

Good luck........Jim

[lamuskrat]

WRONG!

I used to install HVAC and whoever is telling you that has no concept of electrical. I am assuming that the "disconnect" (trade name for service box you are attempting to mount) is for a 120v sytem. You should have a blk, a wht and a grn wire. Blk and Wht go to the fuses and grn goes on the ground lug. If the system is 208v/220v you will not have a nuetral. Should be 2 blk wires and a green.

Pull box should have 2 fuses (amp protection based on size of condenser unit tonage). A schmeatic should have come with it.....if all else fails follow the included destructions (lol...instructions)

Note: Nuetral and ground are NOT the same. One is a return path of electricity back to the panel (in simplistic explaination) and the ground is a protection carrying electricity away to ground or earth ground. If you look at your wall outlets the ground is bare but does not land the same place as the nuetral.

You can always look the manufacturer up on the net and see if they have a wiring diagram or call them.

[shanenin]

Should be 2 blk wires and a green.

the system is definaely 220volt(it is coming monday). How could there be no neutral? Doesn't the electriciy need a return path? two hots and a ground seems unfeasible.

Edited August 6, 2005 by shanenin

[JSKY]

On 220, you have two 110 lines coming in and one return lead. The two 110 lines together create the 220 line when combined.

[shanenin]

a niebor I talked to said with a 220 system, the 2 hots also act as the return path, could someone explain how this could be possible, or at least back it up as a true statemant.

[bozodog]

Oohh man. Pay an electrictian to drop by for a consult.. Best $75 you'll ever spend. Don't you need a permit to do this install? The inspector will help you too. You also need the proper guage wire. I'm not sure why you are not running from a 220 breaker direct from your power panel, to the sub box. (disconnect) Here in Michigan, you also need a GFI circuit for any outside wiring.

[shanenin]

I feel confident with my skills. I just have never wired anything 220. I just thought it was interesting that 220 appliences do not use a neutral, in some way they can return current along the hot.

Edited August 7, 2005 by shanenin

[hitest]

I feel confident with my skills. I just have never wired anything 220. I just thought it was interesting that 220 appliences do not use a neutral, in some way they can return current along the hot.

<{POST_SNAPBACK}>

I'm confident in your skills too, shanenin You rule as a computer technician.

But, if you're the least bit hesitant about this wiring job I would get a professional to at least advise you, tell you if you're on the right track.

Just a thought, I know it's none of my business.

[Chappy]

I also made a living for 20 yrs installing heating and air conditioning systems...but its not a good thing to try to describe how to do that like this.

I strongly suggest that you hire a qualified electrician to wire this for you. If I were close by, I would do it for you free, but....well...

[shanenin]

I am confident I am doing everything up to code. I guess I was more looking for some answers on electrical theory.

I apprecate all of your cautious comments.

[irregularjoe]

I am confident I am doing everything up to code. I guess I was more looking for some answers on electrical theory.

I apprecate all of your cautious comments.

<{POST_SNAPBACK}>

A commom misconception among homeowners is the "220" is "220".

It's not. For most single phase 220 volt AC units, it is just that. Two hot feeds (110 each and a ground wire. No Neutral. The size of the wire is very important. It is decided by the load of the unit and the size of the circuit breaker.

In a different scenario, say an electric range, you would now be dealing with a 110/ 220 volt system. Here you have 2 hots, and a neutral and a ground. Most code now requires the neutral and ground to be terminated at seperate terminals on the range. The reason for the 110 /220 is that the range doesn't need full power all the time. When you are simmering something on low heat, it's probably only using 110. Crank up that broiler though, and you're now using 220.

If at all possible, always connect the ground to the chassis of the appiance and the neutral to the neutral teminal.

If you are NOT using a sub panel, the ground and neutral can be terminated at the same common ground bar in the main service panel box. However a sub panel must maintain seperate ground and neutral terminal bars.

Joey