Help, shower cable overheating

[Thebear101]

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?

 

[trev]

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.

Have you checked all terminations are tight? What were your test results?

 

[telectrix]

Sod it I'll have a bath. :smilielol5::smilielol5::smilielol5:

a manc having a bath and it's not xmas. i don't believe it.

 

[Geordie Spark]

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.

How many of these have we had???

Leccy zipping along a bit of wire is the same for an overhead electric crane as it is for an electric shower surely???

And, are you sure about the size of the cable you're using?? (NOT that it has anything to do with your busbar getting hot though)

 

[Silly Sausage]

a manc having a bath and it's not xmas. i don't believe it. View attachment 26181

It's time for my weekly shave, see ya later.

 

[Plonker 3]

I am an electrician but don't have much domestic experience.

give us a break, it's not just domestic cables that can get hot you know. Do the correct thing and call a competant spark to find out what is causing it.

 

[Richard Burns]

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

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]

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]

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]

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]

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]

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]

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]

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]

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]

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

 

[Thebear101]

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]

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

 

[ipf]

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

 

[Guest77]

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]

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.

 

[1stfix2ndfix]

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!!

Thry didn't teach me that at college and every sparky I've worked alongside has just used normal screwdrivers. Must see if I can get one

 

[stevey1983]

Have you calculated the correct cable size for the shower and distance? 12kw 100m from the board will get the cable hot

 

[DPG]

Ha ha. Daz

 

[trev]

Thry didn't teach me that at college and every sparky I've worked alongside has just used normal screwdrivers. Must see if I can get one

Unless you're terminating cables you'll not need one, at your level I don't think you should be. Not yet anyway mate.
Keep your cash for now and get it when you need it. Remember, it's yet another bit of kit that will need regular (for that read regularly expensive on a mate's wage) calibration

 

[DPG]

I was actually laughing at post #46, but post #47 is quite good as well. 100m away - possibly! Daz