[donf]

This place is scary.

Sunday after a small winter storm passed by, Power in two receptacles in my office, lighting and receptacles in a spare bedroom and one receptacle in the master bedroom (a common wall) all failed. Of course the TV signals went out.

I started looking for a loose Neutral in my office. What I found using a NC stick was voltage to all slots in the receptacles. However, using a meter there was 0 (zero) volts.

When I got the receptacle out, I had 120 Vac between Neutral and ground and 120 Vac between Hot and ground. I verified that there was 0 (zero) volts between Neutral and Hot. My thinking is that there was zero volts because it was the same phase.

Once I opened the Neutral connection and then re-installed Neutral, all of the lights and receptacles worked fine.

Directv was out on Tuesday and said that the power control box for the satellite dishes had fried. He replaced the box. Now I'm curious as to what happened inside that box to cause me a Neutral failure in 3 different rooms?

Any ideas?

[shuntripper]

Poorly made up connection possibly, loose and waiting for whatever would break the camel's back and cause the failure.

What concerns me a little is that when you lost the neutral you read 0 volts between neutral and hot, which after confirming that both read 120 volts to ground, does indeed indicate they are the same phase.
This may indicate that you have two circuit breakers of the same phase sharing a neutral, which could be the proximate cause for your loss of the neutral connection, namely an overloaded neutral with a less than optimal connection in it.

And also guessing that you found the location of the problem because you read 0 voltage between neutral and ground and between hot and neutral at that receptacle

[donf]

"and also guessing that you found the location of the problem because you read 0 voltage between neutral and ground and between hot and neutral at that receptacle"

The voltages were 120 between Neutral and Ground. 120 between Hot and Ground. 0 between Neutral and Hot.

Now that you mention it, the breaker was a split 15 amp breaker. I had some standard 15 Amp breakers so I replaced the split breaker with 2 standard sized breakers.

However, changing the breakers did not correct the failure. The failure went away when I removed the Neutral from the receptacle and then re-connected it.

[tkrussell]

The arcing at the loose connection could have created a high voltage transient spike, or if this is a shared neutral, could have imposed abnormal voltage to the power supply.

This power supply should be protected by a surge protector, providing the receptacle is grounded properly, as surge protectors only work if grounded.

[donf]

TK,

Are you talking about a whole home surge protector on the main service panel or a surge protector on the individual circuit?

When I get home this evening I'll verify that each branch circuit has its own Neutral. It's a rat's nest (no offense to the rats) of wiring in the box.

[tkrussell]

Surge protection should be done at three levels, typical for commercial and industrial, Main, Distribution, and branch circuit or at point of use.

In residential, 2 level is adequate, at Main Panel, and at point of use.