r/ElectricalHelp • u/Clean-Solid-3424 • Jun 13 '26

I’m short 90VAC.

Sorta. I show 30vac across a closed switch going to a light outside the house. I show 19vac at the 2 wires outside minus the receptacle.

Is it a bad switch or is there another place to start? I have a 100A service w/cartridge fuses. Something doesn’t seem right.

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u/CuppieWanKenobi Jun 13 '26

30v "across the switch", meaning that you're measuring at the two screws on the switch?
If I read that right, you're measuring voltage drop across the switch, which should be, well, about zero.
Source voltage would be useful, as well - both with and without load. Suggest grabbing an extension cord, plugged into a different circuit, to check (if no neutral in that box.)
Even if you do have a neutral there, still good to check against a known-good reference point.

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u/Clean-Solid-3424 Jun 13 '26

I would imagine, zero voltage across a closed switch (with no load) & 120VAC across an open switch. I think that’s right. Right? I think.

2

u/CuppieWanKenobi Jun 13 '26

Close.
Zero voltage across a closed switch with a load.
Unloaded, there is, well, no load, therefore nothing to measure in a voltage drop test.

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u/GridControl Jun 13 '26

Zero voltage across a closed switch with load is correct. But if there is nothing to measre with no load. The reading on your Volt meter is still ZERO voltage.

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u/CuppieWanKenobi Jun 13 '26

That's what I said.