Electronics > Repair

Question about voltage in U.S. house built in 1890

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niemand:
Most of the electrical outlets in this house is the 2-slot type with one slot wider than the other. I plugged in a grounded extension to a 3-slot outlet (valid grounded). I have a digital voltmeter set to AC volts, the black probe inserted into the ground of the extension, and the red probe inserted into the narrow slot of the 2-prong outlet. The reading I got was 62 V. The reading I got when I put the red lead into the wider slot of the 2-prong outlet was 59 V. Why not 120 V (the U.S. standard household voltage)?

When I measured only the 2-slot outlet (i.e., inserted one probe into the narrow slot and the other probe into the wider slot of the same 2-slot outlet), the meter read 120 V.

bdunham7:
What does your service panel or fusebox look like?  Unless this has wiring from the 1920's that hasn't been updated, something isn't right.  The neutral (the large slot side) should be bonded to ground at the service panel.  I'd suspect you don't actually have real grounds and perhaps your system isn't actually ground referenced (this would be extremely unusual in the US).

BlownUpCapacitor:
The electrical wiring in that house is not ground referenced, meaning neutral is not connected to ground; that's a big no no.

Whales:

--- Quote from: BlownUpCapacitor on May 14, 2024, 04:51:55 am ---The electrical wiring in that house is not ground referenced, meaning neutral is not connected to ground; that's a big no no.

--- End quote ---

It sounds more like the ground wiring is not ground referenced.  The neutral wiring may or may not be grounded.

If a house full of appliances has its ground wiring disconnected and floating: measuring the ground wiring to be halfway between active & neutral sounds like a plausible symptom.

I recommend you get a sparky to check this out niemand. They'll have the tools and skills to diagnose the problem quickly. 

Out of curiosity I'd love to see pictures of your fuse boards, BUT, given what you have described any metal cased appliances in your house may be unsafe to touch.  Even the metal cased fuse boxes might be UNSAFE to touch or open.  Could also just be a high-impedance phantom voltage, but don't take the risk.

BrokenYugo:
Pretty typical in a place like this you'll find people have added 3 prong sockets to the 2 wire circuits, leaving the ground floating (this is acceptable if a GFCI is used and marked appropriately) or worse yet connected to neutral to give a "bootleg ground" those are illegal for good reason and should be removed if found.

Assume nothing with power in old houses, you can often find a different era of hacked up old wiring in every room. Sockets with live/neutral reversed are also dirt common.

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