220 volts

S

Steve6

Joined
Sep 29, 1999
Messages
128
Has anyone added 220 V outlets to their shop?

I've added 110 V outlets before and thought that it couldn't be much easier, but I've never wired one for 220 V.

I'd like to add one or two outlets near / next to the main breaker box (within 3 feet of it).

Any comments or suggestions regarding 220 V would be appreciated.

Happy New Year and thanks in advance.
 
Steve, adding 220 is easy but you have to be careful about the load you pull. I don't know how power is supplied to your shop but for a minute lets assume you have a 120 line going in to the shop from the breaker box in your house. Let's further assume you have a 20 amp breaker feeding the shop.

when the service comes in to the box it comes over two wires. Both carry 120 volts at whatever the fault current for the transformer for your line is....say maybe 1500 amps. There is a third wire, bare and that is a netural wire. Now this is AC and goes +- 60 times a second but you need to think of it as DC with a positive wire and a negative. In the panal the black wires will be positive, the white will be negative and the bare will be ground.

From the 20 amp breaker to your shop you have the three wires "B,W,Gr.
All you need to get 220 is have 2 legs of 120 and the netural. There are a couple of ways to do this. You can cheat inside and take one leg of 120 and split it to two legs. You will be very limited in your amperage then. (Volts X Amps = Watts so determine your electrical needs from this formula) You will only have about 10 amps MAXIMUN for that circuit. In reality it will work out to more like 8.

A better way (The other was a jackleg trick) is to put a 220 volt breaker in the panal and run a 3rd wire to the shop. It's a little more digging but is Safe and will run your equipment more efficiently. A third reason for punning it in properly is due to the split in the shop itself with Jackleg method 1, the voltage will be running slightly out of phase. Standard inductive motors will take that in stride but some of the newer electronic controls want to go back to mama.

A third method and sort of a Kinda Jackleg procedure is to run a 3rd wire from the box but connected to another 20amp, 120 volt breaker that does not have a lot of load on it. This works OK and is better than method 1 but not as good as method 2. The danger here is having an excessive draw on one leg, poping one breaker and burning your motor up because it's running on 120.

Now that I've confused you....have fun:eek:
 
First get a voltmeter and instructions to use it.

Pull a three wire connection from the fuse box to a fused disconnect outside the fuse box.

Run your circuit from there.

This route avoids trying to find a fuse or circuit breaker in the box to hook up to.
 
Georges plan does make it a little easier but remember that in case of catastrophic failure, the main disconnect in the house will not shut down the shop power. By-the-way, don't let the electrical inspector see any of these methods. George's plan is the only one that comes close to code and it will only be approved (in most areas) if it feeds off the master disconnect.
 
In every case the incoming mains must be switched and fused. It is not permissable to run circuits until after the fuses. The secondary breaker that I suggest will come with both breaker and a second set of fuses and should met any US or Canadian code.

There are other ways to meet code but this is the safest.
 
An easy way to wire your shop might be to check how other 220 volt appliances are wired and replicate that. Electric dryers and stoves are good examples. All you need to check is how many amps you want for your circuit. Remember to turn off the main breaker, and remeber that the wires feeding the main are still live and will kill you.
 
Adding a 220 circuit is no more difficult then adding a 110 circuit. The easiest and safest thing to do is to stop by a book store and pickup a book. The time live advanced wiring book is fairly decent and will tell you how to calculate and install the 220 circuit. Good luck.
 
If earth fault is a risk, an isolation transformer 110/220 might be a good idea.

TLM
 
Actually TLM, while I havnet begun my apprenticeship YET, I do belive that if earth fault is at risk, the accepted code is to use a GFCI outlet or breaker.

In case you dont know, the nanosecond it detects current running through ground, it immiedeitaly cuts off all power to that outlet. It happens so fast that is has saved many lives and people from getting maimed.
 
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