Tripping electric shower

[stoutlad]

Hello, I've read a few similar threads online but none come up with an answer.

I've had this particular 9.5Kw shower for 3-4 years and has run without problem. A few days ago it it just cut out after about 4 or 5 minutes and set off the trip switch which is a Proteus B45. Firstly after reading some stuff I tightened all the connections in the shower unit and in the isolator switch outside the bathroom, it is the type like a cooker switch but with 'Shower' written on it. Same thing happened again but seemed to be after only a minute or so this time. Since the shower is used a lot I decided that it just must be on it's last legs so bought a new one only to discover the same thing happening again. I replaced the isolator switch outside the bathroom and still no better. The only thing I have not tried is replacing the actual B45 trip fuse thing but I figured if that was the problem it simply wouldn't work, would it?

Some details.. 9.5Kw Triton replaced with 9.5Kw Triton with a different model name but exactly the same fittings, I didn't have to alter anything at all to fit it in, think it must be same model but new name. Nothing else is connected to the shower circuit, the cable runs from it's own box next to the main fuse box directly to the isolator switch outside the bathroom then from there, through the wall to the shower. It is 10mm cable.

Any ideas as to the cause?

 

[ringer]

Stoutlad, it sounds like you have done a pretty thorough job as far as you are able to. Unfortunately it is now time to call in the experts who will have proper test equipment. It might possibly be the MCB (trip switch as you called it) or it may be some kind of fault in the cables supplying the isolator switch and the shower. In either case, you should let a qualified electrician do this. If you post your location, there might be a member here who lives nearby and can help you.

 

[stoutlad]

Thanks, I have already contacted an electrician and left a message on his answer machine, he will probably not be in until tonight. I just wondered really if it was worth wasting any more money by buying another 45a trip switch. I have already wasted £120 on the shower, tenner on the isolator switch and a fiver on a packet of brass olives for the pipe. If the trip was pretty cheap then I might try it, however I would still want him to check it all out even if it did work but he can't always come like right away or next day even

 

[telectrix]

is the circuit RCD protected? if not, then that is another issue that needs addressing.

 

[Spoon]

dont bin your old shower, you can use it for spare parts if anything goes wrong with the new one. Same goes for the switch.

 

[ringer]

Tel, as he is replacing like with like and not running new circuits or altering the characteristics of the existing circuit, then there is a valid argument that RCD protection is not required. Naturally, it would be preferable to have RCD protection, but not absolutely necessary in this case.
Stoutlad - post your location (village/town/city) and a nearby member might just be free to attend today if you're lucky.

 

[stoutlad]

I don't think it is RCD protected but I wouldn't know. Where would the RCD protector be, is it a plug in type of thing or what? There is only one plug-in type of thing and that's the B45 trip switch. I'm in Scottish Borders but I always get the same lad for my electrics, he is self employed

 

[telectrix]

Tel, as he is replacing like with like and not running new circuits or altering the characteristics of the existing circuit, then there is a valid argument that RCD protection is not required. Naturally, it would be preferable to have RCD protection, but not absolutely necessary in this case.
Stoutlad - post your location (village/town/city) and a nearby member might just be free to attend today if you're lucky.

totally agree. my thoughts regarding RCD, though are based on the fact that manufacturers instructions with the new shower may well call for RCD protection. also, if there is a problem with the cable/s and replacement is necessary, then i would say that RCD is essential.

 

[SPARTYKUS]

My moneys on a cable fault

 

[spark 68]

Mines on the Proteus B45 MCB, other Shower may have been faulty after all, and now weakened the MCB.

A few days ago it it just cut out after about 4 or 5 minutes and set off the trip switch which is a Proteus B45.

 

[SPARTYKUS]

You're on


He forgot to mention a pictures been hung on the wall where the cable run is :banghead:

 

[Engineer54]

MCBs are not infallible, We always have a number of them that fail on our projects, some straight from the box others during use.... Difficult to test MCBs, especially for normal electricians who would not normally have the expensive test equipment to do so!! So left with trying like for like exchange units....

 

[SPARTYKUS]

Cable fault

 

[telectrix]

a clamp meter would be useful, with a new MCB to hand.

 

[stoutlad]

Is there any possibility that it could be the water pressure? The Water Board have been working in the area for weeks supposedly 'improving the water in your area'. I never thought to watch the low pressure indicator on the shower unit up to the point when it cuts out but the low pressure light was definitely not on when switched on or for at least the first 15 seconds or so. We have had no warning from them of the water pressure being low

 

[telectrix]

generally when the water pressure is too low, the shower heater switches off and you get a cold shower. saves a bit on the leccy though.

 

[spark 68]

If the water pressure is low then the pressure switch inside the shower cuts the power to the heating element, this wouldn't trip the MCB.

Just out of interest, how many times did you try to re-set the MCB ?

Beaten to it by Tel, must type quicker lol

 

[stoutlad]

If the water pressure is low then the pressure switch inside the shower cuts the power to the heating element, this wouldn't trip the MCB.

Just out of interest, how many times did you try to re-set the MCB ?

Beaten to it by Tel, must type quicker lol

I think about 4 or 5 times with the old shower and twice with the new one. The first time I tried the new shower I tried it on the coldest setting then switched to the next setting up then finally the hot setting and in all it lasted about maybe 4 minutes. The next time we tried it (after changing the isolator switch) we set it going on the hot setting straight away and it tripped after about 1 minute or not even that

 

[telectrix]

without the appropriate test gear and the knowledge to use it, afraid you are peeing into the wind on this one.

 

[stoutlad]

.. another thing, the old isolator switch has 45amp written on it but the new one has 50amp written on it even though in the shop it had 45amp written on the price ticket sticker (B&Q) does that make a difference at all?