Why Always The Neutral?

[Stoneman]

Hi,

Been browsing the site after an absence - thanks to a reminder from Admin!

Something I've been meaning to ask/post for ages...

I went out to a fault over Christmas - RCD trip problem... gave usual advice over phone (unplug everything then try a reset) - hoping this would sort it... I didn't really want to go out at 7 at night.

To cut a long story short, I eventually found a burnt neutral in a socket which had eventually touched earth.

The old dear always irons from this socket so it is well used/loaded.

Trimmed back neutral, crimmped an extension and replaced socket - job done.

But it reminded me to post a question - why is it nearly always the neutral conductor that burns?

In my experience, this is usually true when 45A switches burn - it's usually the neutral. It might be just me, but I often come across it. I'd expect the neutral terminal to be loose, but they're often tight.

The neutral is still a line conductor and must be carrying the same current as the Live?

Have a great New Year!

 

[apprentice87]

I find this too, but what makes it even more mystifying, is that we are talking about AC, so what is the difference between the two..

john....

 

[kerching]

I have often wondered why this happens.

After 40 years of thinking about it I have concluded that 'it is just one of those,things"

Just saying

 

[Blue Duck]

Potential difference ?

:C

 

[Andy™]

because its less important than the dangerous live so doesnt get tightened as good?

or the electric is racist and doesnt like black... good thing we changed wiring colours, itll now move onto the live instead...

 

[revjames]

I'm not getting involved...... I'm staying neutral..... :slap

 

[DarkInferno]

My vote is it doesn't get that last tweak for tightness or the same care when dealing with the cable as the live, as if its not quite fully home in the connector it doesn't matter as much... or people are more willing to bend and twist the neutral while its connected into the fitting to ensure that the line is fitted correctly. 

 

[Badger]

The simple answer here is the neutral is the load side of the appliance where as the love desnt have the load sitting on it the neutral does it takes more of a load bashing if you know what I mean

 

[ProDave]

The simple answer here is the neutral is the load side of the appliance where as the love desnt have the load sitting on it the neutral does it takes more of a load bashing if you know what I mean

:shakehead  

Started the celebrations early? 

 

[Stoneman]

See what you mean Badger...

But, the current flowing in N still can't be more than 30mA different to the 'love' current ...  lol!

So.... Why does the N burn out first?

I'm not losing sleep over this... Just don't like 'not understanding' Something!

Darren.

 

[SPECIAL LOCATION]

Whilst I agree the neutral is very often the "burned out" connection....

It is not always the neutral.....

Heres a shower switch I replaced at the start of December...



Note its the brown "live" thats more brown than it should be!!!!!

Assuming the correct cable size for the load and correct over current protection is fitted...

then any overheating - melting - burning out at joints is simply due to the mechanical robustness of the joint!

you could toss a coin 30 times and get get 2 heads, 20 tails, then 5 heads, then 3 tails... 

even though that set of results suggest you get more tails than heads...

Its still a 50/50 chance which one you get!

same with the overheated cable joints IMHO.

Guinness

 

[septiclecky]

I'm not getting involved...... I'm staying neutral..... :slap

You religious types always sit on the fence, never getting involved.

 

[kerching]

Or........do we just remember it more because it is the neutral, and is thus in our minds "unusual"?

Just....wishing that i had had more to drink last night

 

[sprocketflup]

The simple answer here is the neutral is the load side of the appliance where as the love desnt have the load sitting on it the neutral does it takes more of a load bashing if you know what I mean

and that's the simple answer apparently, just wait till you see the tricky one....

 

[copperknob]

mmmm, interesting point this. Not called electrickery for nothing you know!

 

[pickleye]

Just fitted 30 vandal proof light fittings, manufacturer fitted flex falling out of the neutral connector on 3 of them. Their push fit connections too, live and earth both ok - go figure.

 

[IzzyS]

Probably because the prescribed testing (R1+R2 and Zs) doesn't test the neutral, so iffy connections are not picked-up.  

Unless of course you exceed the minimum testing requirements and add in a quick (R1+Rn) and/or a line-neutral loop impedance test.

 

[Sidewinder]

Ahh now Izzy, you may have nailed something there.

If you don't do a L-N loop test, without calculations, and a L-N loop value @ the origin, how can you meet the requirement, for verification of volt drop?...

 

[Blue Duck]

Volt drop, loop tests ??? What are you blabbering on about???





The ocpd



courtesy of bobski the builder.

 

[Andy™]

i know what happened there... someone forgot the earth sleeving!