Electric question

Looking at an electrical box (wall switch box) - helping a friend.
 
How would it happen to see one wire at 120VAC and another wire at 280VAC?
 
This is with VOM checking 3 wires in conduit.  No color matching here.  (no white or black wires and only blue, red and orange wires?)
 
Wire 1 - wire nothing except one time saw a 120VAC load using metal box neutral
Wire 2 - 120VAC load - using metal box neutral
Wire 3 - 280VAC load - using metal box neutral
 
Used box once for neutral and saw the above loads.
 
I have never seen anything like this before.
 
No neutral wire in box that I was able to test with VOM.

Could be this.  Although 280V doesn't make much sense.

Also kinda strange to have both phases going to the same box.  But there are two phases coming from all normal residential boxes.

This one shows it from the breaker panel perspective:
 

Thank you Sam.  That is what I expected to see with the two wires with AC on them. 
 
Yup and there are some 3-4 sub panels sprinkled around the house which I didn't look at and have no clue about.
 
The original oldest panel in the house is over 50 years old.
 
I have seen mickey mouse electric but never like this before.
 
The AC on the one wire went from 280VAC to 300VAC which I have never seen before.
 
The none connected to neutral wire did have 30VAC on it though and then 120VAC on it which didn't make any sense to me.

Have you made voltage measurements back at the main panel?  How about voltage measurements between wires 1-to-2, 1-to-3 and 2-to-3?
 
I can't explain how you could see such voltages if this is a normal residential situation.  Right now, I'm wondering if the metal box isn't providing a good ground reference and that is part of the problem.

This really sounds like you have discoverd a problem with the electrical service to the house. Go to the main breaker box and check the voltage between L1 and L2  and neutral there.
 
Mike.

Sounds like a commercial application where there's a transformer tap at 277. Could also have a buck boost transformer installed somewhere.
 
Not a common item to see in a residence.

I think you're looking at 3 phase here. One give away is the lack of black and white conductors. A few years ago my son bought a house that had 3 phase in a backyard shop for some power tools. The power company had installed a tapped transformer to obtain 3 phase power from a single phase distribution line. Exactly what DEL is talking about.
 
Can you find the panel that feeds the location in question? If it is in fact 3 phase the panel will have 3 hot buss bars in addition to a neutral.

When I bought this house in 1996 I had a power strip that started beeping that there was a low voltage condition and when I looked at the main panel we were down to nearly 100 volts on each line. I called the electric company who confirmed this at the pole and later came back to the house to tell me that the entire neighborhood had a problem and that they resolved it. It has been fine since.
 
Mike.

Thanks guys.  There are more issues.  More room switches with two loads (280+VAC) and no neutrals.
 
3 rooms have multiple toggle UPB switches with links to switches in I cannot find.

pete_c said:

Thanks guys.  There are more issues.  
 
3 rooms have multiple toggle UPB switches with links to switches in I cannot find.

Click to expand...

Pete
 
Are you saying that Upstart is finding switches that you can not physically find in the house?
 
Mike.

I have been removing UPB switches and switching over to regular switches. 
 
Family room has an old style multiple UPB button / toggle switch with links to switches I cannot find. 
 
Same as a bathroom.  I haven't used Upstart.

pete_c said:

I have been removing UPB switches and switching over to regular switches. 
 
Family room has an old style multiple UPB button / toggle switch with links to switches I cannot find. 
 
Same as a bathroom.  I haven't used Upstart.

Click to expand...

 
I suppose that upstart software won't be able to see any devices unless you can physically find the device first and put it into program mode. Maybe you can have one person press the button while a second person walks around the house listening for the buzzing sound.
 
EDIT
 
The button in question may be controlling an outlet that has nothing plugged into it which would be very difficult to find otherwise.

Thanks Mike.
 
I heard the buzzing sound when playing with switches out of the switch box.  I didn't think of listening in the attic for the sounds (very hot there and full of stuff.  Can't walk around up there at all).
 
The button in question may be controlling an outlet that has nothing plugged into it which would be very difficult to find otherwise.
 
I think the UPB switches or modules are buried in the attic (which I looked at but didn't find any UPB switches/modules) and in the basement they are buried in the ceiling (for lighting) above the acoustic tiles.
 
This is problematic as removing the switches there are no wires from the loads to the switch boxes.

In another message thread RAL posted a link to a very good document concerning proper grounding of a residence and protection from damaging transients. In it there is a possible explanation to the very high voltage reading that you were seeing in you friends house.
 
The entire document is a good read but first take a look at "Open neutral events" starting on page 10.
 
http://lightningsafe.../IEEE_Guide.pdf
 
Mike.