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Discussion Starter · #1 ·
Below is an image of an old 240v outdoor box, that feeds an outdoor central air conditioning unit. The AC is 240v, but there are two fuses on the lines, and though one is white, taped black, I'm not sure what I'm looking at, and hoping those are two 120v hot lines. I want to pop out the side port, and run flex cable to a new outdoor box I will place next to it, to supply outdoor 120v receptacles.

I'm unfamiliar with old boxes of this kind, and a little confused by my readings.
I want to know where to tap in to send hot, neutral, and ground to the new outlet box, if possible.

Here are the readings, key to numbers on photo.

1 - 2 = 240v
3 - 4 = 240v
1 - 5 = 120v
2 - 5 = 120v
3 - 5 = 120v
4 - 5 = 120v
3 - 6 = null
4 - 7 = null
1 - 6 = null
2 - 7 = null
1 - 4 = 240v
2 - 3 = 240v

House is behind box, port at bottom feeds AC unit.
AC is on it's own 240v breaker in panel.
This is the only place outside the house to tap into, and I really need 120v outdoor service.
No exterior outlets on this old house.
There does appear to be one other single lead tracking the pipes from house to AC unit. A ground? A neutral?

Is this just a 240v line from the panel, and no way to do this job?
Why am I getting 120v readings when testing apparent hot and neutral lines to what appears to be ground bus?
Can you see any safe way to pull 120v from this box and out side port?

And yes, I know enough to cut power at panel while working.


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Super Moderator
17,331 Posts
The A/C should be a dedicated circuit.

There is no neutral at the disconnect to allow a 120 circuit.

6,730 Posts
Just a little input on your voltage measurements.
Your readings on 3-6 and 4-7 were null because you were testing the fuses, knowingly or not.
If they were blown, you would have had voltage present.
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