service neutral

[Peter Louis]

Is this one a concern? IS it possible a failed service breaker?

[Nick Ostrowski]

Kind of looks like anti-oxidant paste on the strands. If there was an overheating condition, you'd see scorching on the sheathing. It does look a bit stained and darker but not enough to tell if overheating took place.

[Jim Port]

Why would you think showing the neutral would point to a failed breaker?

If the main breaker had failed there would be no power.

[John Kogel]

Here's a scorched connection for comparison. 1974 Al wiring. This white wire is still doing its job, but needs repair. And it should have been marked red or black.

As a matter of fact, this wire has been spliced once already. A 15 amp 240 volt breaker is supplying a 40 gallon water heater through a compromised Al feeder. I hope the electrician will do the right thing here for my clients.

[Peter Louis]

Thanks.

I mean failed to trip once overload.

[Speedy Petey]

I mean failed to trip once overload.How could you possibly know this?
What are you basing it on?

[Peter Louis]

How could you possibly know this?
What are you basing it on?

That may be a dumb imagination.

Since the discolored neutral terminal, if the service breaker tripped right away, there will not be overheat on any terminals.

[Jim Port]

You could have a terminal overheat well under its ampacity and not trip a breaker. All you need is a poor connection.

A neutral on an improperly wired multiwire branch circuit could be carrying 2x the current of the hots. This will not trip a breaker either.

[Speedy Petey]

That may be a dumb imagination.

Since the discolored neutral terminal, if the service breaker tripped right away, there will not be overheat on any terminals.What Jim said.

It is absolutely possible and even likely that a poor termination will overheat to the point of melting without ever drawing too much current on the circuit.