Help, shower cable overheating

Thebear101 · Sep 8, 2014

Hi I've fitted a new shower with a 10 mm cable connected from a 45 amp breaker (neutral to neutral bar and earth to earth bar) to a 45 amp double pole switch then to the shower. Once the shower has been running for about 10 mins the neutral in the consumer starts to seriously overheat, any ideas on where I've gone wrong?

Richard Burns · Sep 8, 2014

Thebear101 said:
I am an electrician but don't have much domestic experience, I thought the circuit was pretty sound. Correct size cable, correct breaker, double pole isolator. Did insulation resistance and continuity tests with no problems. Was just looking for some help.

This is a very basic thing of a loose connection providing a high resistance joint, the high resistance generates heat as the current flows and leads to things like this

[ElectriciansForums.net] Help, shower cable overheating

Try reading this thread as well.

Usually a loose terminal, either on the manufacturers side or your side, but could also be insulation trapped under the screw.
These are things you should be aware of in any electrical capacity.

Thebear101 · Sep 8, 2014

My first guess is because there's a loose connection and it's arcing, I screwed the terminals as tight as I could get them

telectrix · Sep 8, 2014

Richard Burns said:
This is a very basic thing of a loose connection providing a high resistance joint, the high resistance generates heat as the current flows and leads to things like this
View attachment 26182
Try reading this thread as well.

Usually a loose terminal, either on the manufacturers side or your side, but could also be insulation trapped under the screw.
These are things you should be aware of in any electrical capacity.

oh dear, richard. i've told you before not to post your failures. tch, tch. lol.

Deleted member 9648 · Sep 8, 2014

Thebear101 said:
My first guess is because there's a loose connection and it's arcing, I screwed the terminals as tight as I could get them

You are not going to get any joy on here if you claim to be an electrician and cant find out why a connection is getting hot. Be honest about your experience and you might get some help.

Marvo · Sep 8, 2014

Thebear101 said:
My first guess is because there's a loose connection and it's arcing, I screwed the terminals as tight as I could get them

Overtightning can make it worse. You didn't give the wire a haircut so it fitted nicer in the hole in the neutral bar any any chance?

telectrix · Sep 8, 2014

and it also depends on what you mean by overheating. it may well get warm through normal use. all them little electrons bobbing about causing friction. cables and terminals are generally rated to 70deg.C. that may seem hot to some. try a temp. probe. see how hot it really is.

uksparks · Sep 8, 2014

Geordie Spark said:
Did you use a Torque Screwdriver to tighten the terminal screws??

This is VERY important - you simply cannot tighten screws without using a properly calibrated Torque Screwdriver!! To do so puts your house at risk of turning to ashes and you and your loved ones being visited by a plague of the pox and pestilence!!

I bet your torque screwdriver is still in the shop.

Deleted member 9648 · Sep 8, 2014

Could of course be a loose link in the neutral bar,or the tail to the bar,or a poor main switch contact,or a poor connection of the 10mm....but being an electrician the OP will have checked that,correct?

Plonker 3 · Sep 8, 2014

wirepuller said:
Could of course be a loose link in the neutral bar,or the tail to the bar,or a poor main switch contact,or a poor connection of the 10mm....but being an electrician the OP will have checked that,correct?

......

telectrix · Sep 8, 2014

how dare you post a pic of my ex-wife in the nude. anyway she uses a broomstick for flying.

Thebear101 · Sep 8, 2014

I've been a time served spark for 4 years, working mainly on ships/marine installations. I'm not a total idiot and understand why loose connections heat up, I couldn't find any loose connections which is why I've posted here to see if I've missed something. Sorry if you feel like I've been waisting your time.

Silly Sausage · Sep 8, 2014

Bear, whenever you can, post up some pictures of the offending gear, it helps enormously.

ipf · Sep 8, 2014

You should have posted some details first, then.....may not have come over as a diy'er.

Guest77 · Sep 8, 2014

Thebear101 said:
I've been a time served spark for 4 years, working mainly on ships/marine installations. I'm not a total idiot and understand why loose connections heat up, I couldn't find any loose connections which is why I've posted here to see if I've missed something. Sorry if you feel like I've been waisting your time.

No of course not, we have one of those called dingle here

telectrix · Sep 8, 2014

bear, you should have given more info in your 1st post. we get so many chancers on here with posts like " i've fitted this and it doesn't work right, tell me why".

just check every connection. clamp meter the circuit, see what it draws. and what may seem hot might just be normal warming. after all, it's around 40A.