how did they manage to overheat _all_ neutrals?

How about a grounding bushing on that RGS entering the panel ??

Is this the result of harmonic currents?

What is this panel feeding?

Looking closely at the several neutral busses here, it appears that the burn/overheat marks are on the conductors which are attached to the top-most buss (the one closest to the breakers). I wonder if a poor connection exists where the two phillips screws connect this buss to the rest of the neutral assembly, causing this entire buss to heat up?

Mike (mamills)

Something here is definitely wrong. Not only the neutral connections to the bus, but even along the length of some of the conductors, it is discolored. HMMMM!!
I am curious what is causing this.

Pierre

It looks like there are several ground wires terminated on the neutral buss, including the ground wire from the UF cable that was in the same conduit as the feeders.

I also was thinking triplen harmonics, but I assume this is a dwelling, and circuit 3 is a GFCI. What non-linear load(s) would you have on a GFCI circuit?

The overheated neutral bus bar and discolored wires aren't the only problems...

Where the heck's the main breaker?

Theelectrikid:
First off, Welcome to ECN!

Chances are, the main overcurrent protection (breaker) is at the source for this panel.. In the eastern side of the USA, it seems to be popular, if not universal to have the power co.'s meter outside with a main disconnect.. This in-turn feeds to a distribution panel elsewhere.. (usually a garage or basement, which is what you see here... Protection from overloads for this type of panel would be at the source it was powered from.. (Main disconnect, branch circuit feed from another panel, etc.)

-Randy

About halfway down the left side of the panel it looks like the phases get mixed up. Look, it goes black, red, black, red, black, red, black, black, red, black, red.

If these are multi wire bracnh circuits that could explain the nuetral discoloration on some of the nuetrals. If they are using 2 legs of the same phase and a common nuetral, the nuetral will carry the sum of both leg's current. It looks like this may have ocurred on the right side as well.

Just a thought.

Hello
I am a trained electricial who will be setting my oral examination in a few weeks. In Jamaica the license exam is a two part.

From my knowledge the problem lies around the following.
(1) The earth loop impedance is very high,as a result the high floating neutral current that is caused from an unbalance circuits have no where to go.

(2) The screws are loose at the neutral bar.


I do not like this panel as it have do main disconnect. In Jamaica if the panel is more than two meters away from the main disconnect then this panel must have its own disconnect

So there is a shutoff outside of the house? Is this something that has a lock so nobody does a "pssst...watch this!" and shuts off someone's power? If there is a lock, how can one quickly shut off power?

Another guess....... they lost a phase, so it got "temp'ed" up using the one remaining live leg.

Thanks for telling me that, Lotzahell.


[This message has been edited by Theelectrikid (edited 07-05-2006).]

If this is a sub panel, where is the equipment grounding conductor? Also the grounding and grounded conductors should be isolated from each other in this panel.

WOW...that looks like a very hot panel !
so hot in fact that the buss with all the over-heated neutrals on it, looks like it's warped up a bit in the middle and even cracked at the top, right in the middle!!!

I can see how the 2 screws that secure the buss could be loose and causing this...looks terrible.....almost like water has dead shorted those top 2 breakers to the neutral buss there at one time or another...