Determining single-phase power sources

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MDOC7

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Hi, I'm new here. I have one question that should be simple:

How do you determine the phase of one leg from another? Equipment that needs to be installed in 2 locations or more in the household must have the same phase; they cannot be out of phase with each other. What is the simplest and effective way to find legs with the same phase?

I'm talking about existing wiring and service boxes, not planning them.

Thanks.
 
Why don't you go back to the load center and check to see which wire is on which leg for each of the loads? If you can not identify one from the other you can check continuity.

What single phase equipment can not have it reversed??

Jason
 
Since you don't appear to be a licensed electrician (I don't mean that in a bad sense) I would look at the position of the breakers in a panel. Start at the top breaker on either side--- that is phase "A" the one below that is the "B" phase then back to "A" then "B" etc. If it is 3 phase it would be the same A,B,C, A,B,C etc
 
I infer this is new equipment, and it is being installed on existing wiring. That tells me you are adding load to existing circuits. For if you were running new circuits, you could select the phase that will supply each circuit. My concern is how you plan to verify that any circuit to which you will add this equipment is not already loaded to its capacity.

What kind of equipment is this, that it has to have each item on the same phase?
 
If it is audio equipment, then it should definitely be installed on new wiring so that the equipment may at least have a dedicated circuit. An isolation transformer would be even better.
 
Dennis Alwon said:
Since you don't appear to be a licensed electrician (I don't mean that in a bad sense) I would look at the position of the breakers in a panel. Start at the top breaker on either side--- that is phase "A" the one below that is the "B" phase then back to "A" then "B" etc. If it is 3 phase it would be the same A,B,C, A,B,C etc
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I've seen some older panels that go A, B, A, A, B, B. It's odd.

Thx,
Jason
 
I solved the question by looking at a sample panel label. (The box is at someone's house inaccessible to me.) The phases are alternating across rows of switches (A,B,A,B). That's easy enough.

Since you asked: the equipment to be installed requiring synchronous phases at locations is Ethernet Over Powerline, Aka Powerline Networking, which provides computer networking over AC wiring.

No, I'm not an electrician, though I'm an engineering technician. Thanks for the help.

Measure the hot side of two distant outlets, and if it's zero volts, it's in phase? Good, thanks.
 
What type of ethernet over power are you installing? We have installed a lot of the Telkonet product and their equipment connects to all phases and any outlet connected to the panel is live.
 
wshoard said:
What type of ethernet over power are you installing? We have installed a lot of the Telkonet product and their equipment connects to all phases and any outlet connected to the panel is live.
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It hasn't been chosen. Among the choices:
http://www.linksys.com/servlet/Satellite?c=L_Product_C2&childpagename=US%2FLayout&cid=1115416874725&pagename=Linksys%2FCommon%2FVisitorWrapper&lid=7472522279B61

http://www.netgear.com/Products/PowerlineNetworking/PowerlineEthernetAdapters/HDX101.aspx

http://www.netgear.com/Products/PowerlineNetworking/PowerlineEthernetAdapters/XE102.aspx

What's the URL for the Telkonet product?
 
OK, well, it's a residential home that we're thinking about installing it. But first we're investigating the source of the interference that's appearing on the wireless routers.
 
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