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Jonspark

Why is it always the neutral that overheats on shower pull switches? I've never seen a burnt live conductor.
 
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it's all down to electrons. they come all the way from the L supply, race through the installation, heat up your megawatt shower, then they knackered and so are slow on the return trip, spending longer at the N shower terminal for a rest, thereby overheating said N terminall. :smilielol5::smilielol5::smilielol5:
 
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bigdavs83 said:
Electrons are racist. They don't like any cable that starts with a "BL". More of an issue than Putin in my opinion.
Click to expand...

hmmm. they used to be OK with black. praps it's colours with a ue in them, anti european, like fagash farage.
 
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telectrix said:
hmmm. they used to be OK with black. praps it's colours with a ue in them, anti european, like fagash farage.
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Haven't you sorted out that problem with dyslexia ... that's the EU don't you know. << Banter! No disrespect or belittling of those who struggle with real dyslexia meant in any way shape or form. No dyslexics should be offended by this post ... please?
 
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here's a burnt live.

[ElectriciansForums.net] Burnt neutrals

80A HRC fuse on a 10mm XLPE SWA . i was called out after FB attendance xmas day.
 
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Jonspark said:
Why is it always the neutral that overheats on shower pull switches? I've never seen a burnt live conductor.
Click to expand...

I love shower threads so !!

Once current has flowed through a fixed resistance the returning voltage drops.
That drop in voltage creates a back emf that is harmonically amplified by an increase in current.

Now the harmonics become resonant, and over time create mechanical vibration that work the terminal screws loose.
This in turn creates a bad connection producing heat.

So effectively if line and neutral are torqued to equal values, over time it is the neutral that becomes susceptible to a loose connection. :icon12:
 
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baldsparkies said:
I love shower threads so !!

Once current has flowed through a fixed resistance the returning voltage drops.
That drop in voltage creates a back emf that is harmonically amplified by an increase in current.

Now the harmonics become resonant, and over time create mechanical vibration that work the terminal screws loose.
This in turn creates a bad connection producing heat.

So effectively if line and neutral are torqued to equal values, over time it is the neutral that becomes susceptible to a loose connection. :icon12:
Click to expand...
And you win tonight's star prize for the correct answer.
 
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Jonspark said:
Why is it always the neutral that overheats on shower pull switches? I've never seen a burnt live conductor.
Click to expand...

Standard R1+R2 testing on a radial carries out no test on the neutral therefore no poor connection in the neutral will ever be picked up. I'm sceptical about this having any kind of statistically significant part to play though.

You have to bear in mind that on AC, if you ignore potential difference to earth, the neutral spends exactly half of its time being the 'live', really :)
 
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