I have been troubleshooting this for some time now. Any help would be great!
A friend of mine's wife plugged in a hair dryer and lost power about 2 minutes into it. A few hours later the power was back on…. nobody messed with any breaker or anything.
Now when she turns on the hair dryer the power goes out and no tripped breaker.
I'm reading 120v one neutral to ground and 120v hot to ground. During my troubleshooting I have disconnected the neutral from the bus and energized the circuit to see what I get from neutral to ground. 120v from neutral to ground at the panel.
Just to see I re-landed the neutral to neutral bus to see if it would trip the breaker, no tripped breaker.
Since no breaker tripped I tested ground bus to neutral bus and got 120v. With that being said I opened the breaker and tested neutral to ground and had 0 volts.
So, I pulled all the plugs out and inspected all the wiring and found no issues.
I can't give up till I find this issue and now the power has returned. Can anyone recommend my next step?
I'm almost thinking a staple has made its way through the insulation on the Romex.
Electrical – 120v on black and white wires
circuit breakerelectrical-panelneutralreceptacle
Related Solutions
The AFCI wire needs to connect to the neutral bus. Put it on the other side, or add on to the length of the wire with a wirenut.
Don't the two hot legs need to be balanced if it's line to line to compensate for the fact that there's no neutral?
No, if there is no neutral then all the loads must be connected across phase to phase. In US terms this would mean that there are no 120V loads that need to be balanced.
I'm not convinced you have two hot legs from a US style split-phase supply.
The Chinese standards seem to be pick and mix of other countries standards. Note that Red=Live, Blue=Neutral, Green/Yellow=Earth is a valid colour combination in Australia.
The four "two-pole earth leakage breakers" (tengen DZ47LE-32 C16) are marked with N for Neutral at one connection.
I would therefore, naively perhaps, expect the blue wires to be neutral and to have zero or very low voltage with respect to the green/yellow ground wires.
I don't see any normal bus connectors, it seems the installer used red wires to construct buses live and instead of the neutral terminal that would be found in a UK consumer unit.
CE marked C16 circuit breakers should be 16A breakers with a "normal" sensitivity range.
The blackening of the top screws of the old breaker is also concerning. Is too much resistance on the wire or screws/breaker a possible cause?
The clamping screws were not done up tight, the cables were not inserted correctly or the switch was passing too much current. Or all three.
Example, for comparison purposes, of an old and unusually neat UK equivalent showing copper bus bars at bottom connecting live feed to single-pole breakers, terminals at top for neutral and ground (these terminals are sometimes also called bus-bars). Note the copper bus bars normally have a plastic shield, and normally there is a cover that shields all the wiring with holes for access to the breakers only.
Since China is not the UK, there may be entirely different exemplar Chinese installations that bear little relation to this. The question shows an installation where every breaker and switch has two poles. This means there is no need for a neutral terminal connector strip. However the neutral wires linking adjacent "earth-leakage breakers" form an improvised bus.
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Best Answer
When things are plugged in to different outlets in different locations, but are all on the same circuit, from that given protective device ( breaker / fuse ) and a neutral becomes disconnected that neutral will become "hot".
Try seeing how many things you know are plugged in to that circuit if possible and you'll possibly find a few things that aren't working...
Somewhere, either behind some receptacle, or in the panel itself that neutral became disconnected.
Envision the neutral as the return circuit for the hot ( which it is ) Whether it goes through a ceiling light, something plugged in it's still running hot as it travels through the neutral, when it becomes disconnected.