Burnt out pull cord to electric shower

[Sammw123]

Hello everyone,

I have recently had a bathroom refurb in our new house as it had no bathroom fitted before. I have a 8.5kw electric shower that is isolated by a 45 amp pull cord. The shower stopped working so I had an electrician come and have a look and the pull cord wires are completely black and the plastic is melted. It never tripped the main fuse box but it is wired into a 32 amp fuse on the main box and the pull cord is 45amp will this cause it to burn? What other options are there for the burning ??? Any advice is much appreciated thr shower is fitted with a 6mm cable but I'm unsure of the size of the cable that goes from the pull cord to the fuse box...

Thanks in advance

 

[SJD]

Loose connections at the pull-cord switch.

They have to be really tight, and on stranded cable, I would tighten again after waiting a few minutes.

 

[Sammw123]

Loose connections at the pull-cord switch.

Hi the electrician said he couldnt see any loose cables to the pull cord and I have just found that the cable going from the pull cord to the fuse box is 4mm if this makes a difference

 

[ipf]

Loose connection at switch. Quite a regular occurrence due to the effort taken to replace the cover and cable movement causing the loosening.
Edit. 4m could well make a difference, as it's undersized, but a loose connection at the switch may not seem loose if it's welded. Weakest point.

 

[Midwest]

45A pull cords are the work of the devil.

 

[Strima]

Very common problem with shower switches. Using good quality switches reduces the problem but it never seems to fully go away.

 

[telectrix]

replace with acrabtree or click 50A circular switch. easier to fit and as reliable as a Toyota.

 

[ipf]

replace with acrabtree or click 50A circular switch. easier to fit and as reliable as a Toyota.

You're right, tel. Started using Crabtree when they were the first to do a 50amp. There was nowt else on the market to touch 'em.

 

[Midwest]

The other thing I find about those pull cords, is that the home owner actually use them to isolate the shower after using said shower.

I mean really.

 

[Sammw123]

The other thing I find about those pull cords, is that the home owner actually use them to isolate the shower after using said shower.

I mean really.

I turn it off after every shower ? is that not right haha

 

[telectrix]

I turn it off after every shower ? is that not right haha

it's not right. it's designed as an isolator. switchig on and off under load shortens it's life expetancy, like me having smoked 40/day for 50 years. i'm getting a bit of a cough and i'm only 73.

 

[Midwest]

I turn it off after every shower ? is that not right haha

I would not bother, your shower has a perfectly decent arrangement to turn it on & off.

Back to your issue, if the cable has suffered thermal damage, it will need cutting back to where the cable is good. That can be some distance, in some cases.

What has your electrician advised, and what has he/she said about the sizing of the cable?

 

[Sammw123]

I would not bother, your shower has a perfectly decent arrangement to turn it on & off.

Back to your issue, if the cable has suffered thermal damage, it will need cutting back to where the cable is good. That can be some distance, in some cases.

What has your electrician advised, and what has he/she said about the sizing of the cable?

The electrician took one look at it and said replace your whole fuse box? I understand the 32amp on the fuse box may need replacing for a 40 amp for the shower but this could be replaced individually not the whole fuse box? He didnt even look at the 4mm cable that leads to the fuse box and just said to call when I want the whole fuse box replacing. That's what brought me here really as that is a expensive job and if there is an alternative I would rather try that first

 

[Midwest]

The electrician took one look at it and said replace your whole fuse box? I understand the 32amp on the fuse box may need replacing for a 40 amp for the shower but this could be replaced individually not the whole fuse box? He didnt even look at the 4mm cable that leads to the fuse box and just said to call when I want the whole fuse box replacing. That's what brought me here really as that is a expensive job and if there is an alternative I would rather try that first

Hmmm easy for me to say, but why does your whole fusebox need replacing, is it somewhat old & tired?

The MCB needs to be sized in accordance with the cable size & how its installed. Likewise, a shower load should be installed with a suitably sized cable & MCB, i.e. the circuit should be designed for its load appropiately.

 

[SJD]

Perhaps post a photo of the fusebox.

 

[pc1966]

Usually the only genuine reason for replacing the CU (consumer unit = fusebox) when something is under rated is when it is so old you can't get compatible parts.
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Already mentioned is that a 8.5kW shower needs an minimum of 6mm cable (and even then not through a thermally insulated route) and generally most electricians would be selecting 10mm cable.

 

[Sammw123]

Hmmm easy for me to say, but why does your whole fusebox need replacing, is it somewhat old & tired?

The MCB needs to be sized in accordance with the cable size & how its installed. Likewise, a shower load should be installed with a suitably sized cable & MCB, i.e. the circuit should be designed for its load appropiately.

My house was built in 1991 I dont know how long they are suppose to last and the 4mm cable that supplied the fuse box comes through the loft. I am thinking a new fuse box may be easier at this point it seems there are lots of faults on the shower cabling

 

[Midwest]

If it was my house, I’d be getting more than one quote to have that fuse box replaced, and a new properly sized cable run to your shower.

 

[westward10]

Have trouble getting a Legrand breaker for that.

 

[radiohead]

An alternative solution would be to replace your 8.4kw shower with a 7.2kw unit, in which case your CU and existing 32a mcb and wiring should be adequate to leave in place. Not necessarily the best option but if your budget is tight...….

 

[davesparks]

The other thing I find about those pull cords, is that the home owner actually use them to isolate the shower after using said shower.

I mean really.

That's the whole point of it, to turn off the shower, no different to any other appliance switch we install.

 

[SJD]

As mentioned by Midwest, get more than one quote to change the consumer unit, prices can vary somewhat (by a factor of 2 or more) for the same thing.

A new consumer unit is notifiable work to Building Control, so make sure anyone who does change it is able to notify it (usually by being a member of a CPS such as ELECSA, NICEIC, etc). And check you will get a certificate with it, which will include test results for all the circuits, again it is not unknown for that to be forgotten!

 

[ipf]

And check you will get a certificate with it, which will include test results for all the circuits, again it is not unknown for that to be forgotten!

Accidentally, of course....

 

[pc1966]

As already said, the ideal solution would be to get a couple of quotes and then get someone in to fix it properly. But just now you might be struggling to get that done.

Failing that, what condition is the existing cable in?
Can you see how far back it has been burned from the switch?
What sort of a route does it take (i.e. do you think you could pull in new cable using the old one as a "draw string")?

As a temporary measure you could cut the cable at a point where it is good and join a new section using something like this:

60A Junction Box

A strong and robust 60A junction box shaped for easier installation in tighter spaces. This oval enclosure has a depth of just 35mm – a slimline profile that’s incredibly easy to work with.Inside, there’s plenty of room and the three large brass terminals are easy to connect. The brown casing...

www.toolstation.com

And replace you burned out pull switch with something like:

Crabtree 50A Pull Switch

www.toolstation.com

Obviously you need to be very careful to isolate the supply, best option is probably to turn all of the power off as you probably don't have a reliable tester. Opening the breaker for the shower should do that, but you should always test!

Never rely on the neon screwdriver sort, they are not reliable, this is the sort of thing you should use for testing and even then you should prove it works on a known live source first:

TIS Voltage Tester

• Voltage range 12V to 690V • Automatic polarity indication • One hand operation for testing sockets• Compact pocket size design• Probe tip protection• No batteries required• Extra bright LEDs• Does not trip RCDs

www.toolstation.com

 

[telectrix]

PM sent to OP. he's a Stokie, so well within reach of my grasping claws.

 

[ipf]

As a temporary measure you could cut the cable at a point where it is good and join a new section using something like this:

60A Junction Box

A strong and robust 60A junction box shaped for easier installation in tighter spaces. This oval enclosure has a depth of just 35mm – a slimline profile that’s incredibly easy to work with.Inside, there’s plenty of room and the three large brass terminals are easy to connect. The brown casing...

www.toolstation.com

Yep. Not like this example of a shower 'failure' from last year.

 

[Midwest]

That's the whole point of it, to turn off the shower, no different to any other appliance switch we install.

Well I know, my wife insists on turning off our electric hob at the isolator, but leaves the electric oven on (at the DP switch), just turns the dials off on the oven. Silly isn’t it?
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PM sent to OP. he's a Stokie, so well within reach of my grasping claws.

Not at the moment, not essential work.

 

[ipf]

Well I know, my wife insists on turning off our electric hob at the isolator, but leaves the electric oven on (at the DP switch), just turns the dials off on the oven. Silly isn’t it?

Ahhh....but she doesn't sit on the oven when ...….. sshh!..

 

[telectrix]

Not at the moment, not essential work.

have said that in my PM. although I can't see why non-essential work should not be undertaken, providing all reasonable precautions are taken. after all, we have Piers Morgan and his crew at work every day. That's not essential ; they could all work from home, or better still give us all a rest from the tripe they broadcast. we can get any news we want from radio ot internet. Likewise the financial scammers that comprise the City of London. Close the tube system and if their work is essential the buggers can walk.

 

[pc1966]

Yes, it is about reasonable risk and what the situation is.

Certainly a repair of sorts is something I would consider important, essential if safety is involved, but not replacing things for decorative reasons, etc.

 

[Pretty Mouth]

I can't see why non-essential work should not be undertaken, providing all reasonable precautions are taken

Agree with this statement. There's nothing in the government guidance that suggests we can only carry out essential work. Point 4:

[Withdrawn] Staying at home and away from others (social distancing)

www.gov.uk

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Exception:

"No work should be carried out in any household which is isolating or where an individual is being shielded, unless it is to remedy a direct risk to the safety of the household, such as emergency plumbing or repairs, and where the tradesperson is willing to do so. In such cases, Public Health England can provide advice to tradespeople and households."

 

[Gary latto]

replace with acrabtree or click 50A circular switch. easier to fit and as reliable as a Toyota.

Tel you got a pic please

 

[freddo]

Tel you got a pic please

Click

Crabtree

 

[Zerax]

...although I can't see why non-essential work should not be undertaken, providing all reasonable precautions are taken.

I'm sure you can do 'non-essential' work... but you are required to work from home if possible. And if you do go to work, you need to practice social distancing.

 

[telectrix]

the beauty of the click and crabtree switches is that you connect cables into the base unit rather than with other types.

 

[Gary latto]

Click

Crabtree

C

the beauty of the click and crabtree switches is that you connect cables into the base unit rather than with other types.

Cheers ill take a look ?

 

[123]

Click also do a square 50A Pullcord which has 2 screws for each terminal and I've not (to date anyway) had any faults or problems with them.

Click 50A DP Pullcord Switch With Mechanical On/Off And Neon (PRW211) - https://www.electrical2go.co.uk/50a-dp-pullcord-switch-with-mechanical-i-on-offi-and-neon.html

 

[Ray Pooley]

Hello everyone,

I have recently had a bathroom refurb in our new house as it had no bathroom fitted before. I have a 8.5kw electric shower that is isolated by a 45 amp pull cord. The shower stopped working so I had an electrician come and have a look and the pull cord wires are completely black and the plastic is melted. It never tripped the main fuse box but it is wired into a 32 amp fuse on the main box and the pull cord is 45amp will this cause it to burn? What other options are there for the burning ??? Any advice is much appreciated thr shower is fitted with a 6mm cable but I'm unsure of the size of the cable that goes from the pull cord to the fuse box...

Thanks in advance

A short circuit to ground can cause an overload situation but it won't necessarily be enough to trip the MCB. It depends on the type of MCB not just the current spec. Do you have an RCD in the consumer unit? A short circuit should have tripped it. If you don't I strongly recommend you have one installed. It might not be a bad idea also to check the current being drawn by the shower once you get the switch replaced. This can be done at the consumer unit. For example, if the shower is 8.5 kW on max you would expect a current of 37 amps which wouldn't necessarily trip the MCB. I know you say you have a 32 amp fuse but that would be ok up to 7.3 kW of load. You probably don't go higher than that in terms of your actual demand. But the MCB is there to protect the circuit. RCDs are there to protect you. So if you haven't got an RCD installed have it done asap.