Rating for Shower Isolation Switch

[Traveller]

I have to install a shower isolation pull-cord switch. The shower is on its own feed from the consumer unit and has its own 30A MCB. The shower unit is a Mira Event XS which has hot and cold water supply and hence consumes only 150w in normal use. The shower unit is fused at 3 amps.

My question is whether I have to install a "standard" 45A pull-cord switch, which seems OTT, or whether I can use a 10A light pull-cord switch. I assume the 10A option is no-go because it won't have double pole isolation? The position of the pull-cord switch is 30 cms horizontally out from the edge of the shower, and 2.4 metres above the floor - so not in Zone 2 - but only just outside!

One reason for raising this is that the switch has to be chrome and the only 45A one I can find is bulky and rated at IP20.

Comments appreciated.

 

[Avo Mk8]

Is this the bulky one?
https://www.cef.co.uk/catalogue/pro...Vjt_tCh2LDQ12EAQYAiABEgIZtfD_BwE&gclsrc=aw.ds

 

[Spoon]

I have to install a shower isolation pull-cord switch. The shower is on its own feed from the consumer unit and has its own 30A MCB.

The manual states it requires a fused 3A supply. The max cable size is also stated at 2.5mm.
How is this wired back to a 30A breaker?

http://www.free-instruction-manuals.com/pdf/pa_1570476.pdf

 

[SJD]

If this is a 30A MCB (rather than 32A), it sounds like an older consumer unit, so just to check does the circuit also have RCD protection?

 

[ChrisElectrical88]

What size is the cable? You ain’t getting bigger than a 1.5 in a 10A pullcord backbox and I doubt it’s that small on a 30A breakerz

 

[ChrisElectrical88]

Why does it matter if it’s IP20 if it’s at 2.4m?

 

[Traveller]

OK, thanks for all for replies.

Yes, the combined MCB/RCD is 32A and it has 30mA sensitivity. the consumer unit is brand new - ie installed about 12 months ago and has MCB?RCD on each and every circuit. I thought the shower unit itself has a built-in 3a fuse so saw no reason not to connect it to a 32A MCB/RCD. However, it seems that is not the case so the pull-cord switch unit presumably will have to be fused at 3amps. Thanks for pointing that out. Not sure about the cable size as I have yet to dismantle the existing switch etc.

IP20 - OK, maybe it doesn't matter as far as the regs are concerned, but the switch will be only 30cms from the side of the shower. In theory at least, it would be possible to direct the shower head directly at the switch becaus there is just about line-of sight visibility from inside the shower - at least for a tall person. I thought IP20 gave no water protection whatever.

 

[ChrisElectrical88]

Why does it need a pull cord, why not just a switched fused spur somewhere other a 3A fuse in it?

 

[Dartlec]

The fusing issue apart, Click Scolmore do a 16A double pole pull cord with neon which you can get a chrome cover for. If the load is fixed then it might be more suitable than a bulky 45A one.

 

[telectrix]

the shower pump should be connected to the ring via a 3A FCU. no need for a separate switch, pullcord or no. the pump only kicks in when it senses water flow as yiou turn on the shower.

 

[Traveller]

Thanks, I had not found the Click Scolmore item - could be good.

The manufacturers instructions for the shower state that a separate circuit must be used back to the CU and since one is already there........... The instructions also specify an isolation switch must be fitted. Maybe the best solution is just to buy a 3amp MCB for the CU.

 

[telectrix]

Thanks, I had not found the Click Scolmore item - could be good.

The manufacturers instructions for the shower state that a separate circuit must be used back to the CU and since one is already there........... The instructions also specify an isolation switch must be fitted. Maybe the best solution is just to buy a 3amp MCB for the CU.

never ever seen a shower pump on it's own circuit. always fed from nearest available point on socket circuit, fused down 3A or 5A FCU.

 

[Traveller]

I think the circuit was probably originally put in for an instatnt head electric shower which would obviously have drawn a lot more current.

 

[Traveller]

I think the dedicated circuit was installed for an earlier instant heat electric shower - hence the need for higher current etc. I guess the best thing to do now is to install a 3amp MCB in place of the existing 32amp one.

 

[Spoon]

So what size cable is currently wired to the shower circuit?