shower switch getting hot

[stl]

Hi,

I have a problem with a wall mounted shower switch getting hot after it has been on for a while (generally near the neon switch). I have read the previous discussions and think it may be to do with how the cores are secured in the switch and would be gartefull for some thoughts on this matter.

Installation as follows:-

MX Inspiration 8.5kw shower at 230v
6mm2 cable
CU with RCD and B40 MCB on shower cable circuit
Cable is mainly in void under floor/bath but part in hollow stud wall (up to switch), part in trunking up to CU and part buried in plaster (up to shower unit).
Switch is a 2G flush mounted MK switch of 50A rating. The recessed box is about 50mm deep.

I know the cable should be 10mm but the shower manual said 6mm was ok for a cable run of approx 17m (which is more than actual) and 8.5kw. Shower was installed when I moved in.

How should the cores be secured in the switch?. Should the strands be twisted together beforre tighting or flat before tightening screws?. Any advice on how to best achieve this (and pushing the cables back in the switch unit) would be appreciated.

I have also noted that the shower head is getting a bit blocked and the manual says this is bad. This may have something to do with it drawing more power and I shall clean this weekend!

Any thougts or help greatfuly received.

thanks

 

[Chri5]

Take the switch face off after removeing the wiring.

Check for pitting on the terminal with a good light, ditto the bar cores of both the i/c and o/g cables.

If the terminals are pitted, replace the switch. If the cores are not bright clean copper, cut and re strip the cable cores.

When it comes to terminating, the termination needs to be done well and the screws firmly tightened down on the cable cores. They should not be fanned out or twisted. The screw terminals will do the work and bite the cable cores.

You may need to gently work the cable cores with pliers, the odd angle on the core between terminal and the main cable sheath will allow the cable to collapse so the faceplate can be secured.
Be careful when using pliers on the sheath part of a cable core, the sheath will be damaged by the plier jaws if you use too much elbow.

 

[sparkwright]

Tighten the terminals fully.
Offer the faceplate up to the wall.
Check the terminals are tight one last time.

Use a decent make of switch like MK or crabtree.

 

[JohnnyG]

Switch is a 2G flush mounted MK switch of 50A rating. The recessed box is about 50mm deep.

Use a decent make of switch like MK or crabtree.

 

[Johnmelad502]

Switch is a 2G flush mounted MK switch of 50A rating. The recessed box is about 50mm deep.

Use a decent make of switch like MK or crabtree.

Well spotted.

 

[FrankE]

My mate has went through 2 MK 50A shower switches.
His shower draws 50.5A and his son spends half an hour in the shower

 

[Monkeh]

My mate has went through 2 MK 50A shower switches.
His shower draws 50.5A and his son spends half an hour in the shower

Then it should not be on a 50A switch, and he needs to educate his son and get rid of the damned money drain.

 

[Steve]

My mate has went through 2 MK 50A shower switches.
His shower draws 50.5A and his son spends half an hour in the shower

Then it should not be on a 50A switch, and he needs to educate his son and get rid of the damned money drain.

Never mind all that, he needs a switch OUTSIDE the bathroom

My grandad would do that when my cousin would come to stay and he'd been in the shower 10 mins (they are on a water meter). He'd shut off the hot outlet from the cylinder

 

[ban-all-sheds]

Yup.

"You can have as long a shower as you like, but only the first 10 minutes will be hot."

I stayed at a French campsite once which had coin-op showers on that basis.

 

[1john]

me too, although i think it was spain, or possibally italy, but you needed a euro to have a hot shower, after the trek down to the shower blocks and realising this i was so tired after a long drive that i just thaught, well it cant be that cold due to the weather being really hot at the time i dont think it could have got any colder, i made an uncontrollable very audiable sound at a pitch so high i didn't think that it came from me initially.