Neutral burnt out more than Lives

[Richard]

Over the years i'v been on quite a few call outs were main switches, RCDS, ect ect have burned out. I'v noticed (I think) that more often than not it seems to be the neutral thats worked loose and not so much the live. I mentioned it in passing to my work college the other day and he said he'd noticed it aswell over the years.

I can't think of any reasoning behind it, sooo, Is their any logical truth in it?

Thanks

 

[JD6400]

Have to admit , thinking about it you do seem right ?
The last one we had was a burnt neutral at the head on 3ph TT farm supply about a a month ago .

 

[Inteificio]

On three phase you can get harmonics upping the N current.

Not so sure on single phase, too sleepy to think it through.

 

[GLENNSPARK]

well...you only need a fairly small difference in tempreture have an effect on the security of terminations....steel having a higher resistance to heat than copper and thus the expansive effect of steel will be less....so as the copper conductor gets warm due to high current demands...then once the demand reduces.....so the conductor cools and reduces slightly....over time this will cause it to come slightly loose....which causes the joint to become more resistive...and thus exasperates the situation.......and so it goes on and on and on...until the conductor together with the termination..cooks....

 

[Deleted member 26818]

It is odd, considering that the supply alternates.
One would expect it to occur equally in both live conductors.
Perhaps it's because of diverted neutral currents?

 

[SPARTYKUS]

Just done one, was neutral. Personally just think it was terminated badly but problem is hard to tell when its a congealed mess

 

[1shortcircuit]

Just done one, was neutral. Personally just think it was terminated badly but problem is hard to tell when its a congealed mess

I was fault finding yesterday and ended up finding a junction box that appeared to have had some form of neutral problem.

Could it be that the live cables get more attention than the neutral when terminations are being made perhaps???

 

[GLENNSPARK]

inert currents in the neutral causing it to heat up more than the line/phase conductor/s

 

[Richard]

Could it be that the live cables get more attention than the neutral when terminations are being made perhaps???

Yes, thats one thought that crossed my mind.

Rich

 

[malcolmsanford]

Triplen Harmonics even in single phase installations.

Most modern electronic equipment have Switch Mode Power Supplies (SMPS) and these all accumulated supplies cause this phenomenon.

http://www.copperinfo.co.uk/power-quality/downloads/pqug/31-causes-and-effects.pdf


This is a good read about it