Electric shower isolation

[Glasgowsparky15]

I'm going to a job tomorrow to fit an 7.5 kW electric shower. One of the boys on the job has ran the cable from the board straight to the shower and connected in to the board ( board is dead ) but all the plastering and wet wall etc has been done so it's just a case of connecting not the shower but there is no isolator switch on the circuit it's straight from the mcb to the shower. It's a split rcd board. I can't find anything in the regulations that states that an isolator switch is required unless I'm missing something obvious. So would it be ok to change the breaker to an RCBO as it is double pole as a means of isolation?

 

[Darkwood]

Local means of isolation as other trades are sometimes needed in the plumbing context... it's been argued a few times but best to just go with the flow on this one?

 

[Glasgowsparky15]

Would this be acceptable though? I know it's not ideal but all the decoration has been done so if possible would prefer to do this. It's a small apartment 2 rooms a kitchen and bathroom so not as if it would be up and down stairs or anything to isolate it

 

[Richard Burns]

An RCBO will not be likely to be double pole, unless you have specifically obtained a double pole RCBO, 99.9% of domestic RCBOs are single pole, so leaving it as is is your best bet, most people do not switch off the isolator anyway!

 

[Glasgowsparky15]

So it is acceptable within the regs to leave it on the mcb then?

 

[Richard Burns]

I believe there is no regulation that states there must be a local isolator.
The shower instructions may state that there must be a double pole isolator, which is then for you to determine if this is acceptable not to do locally as the main CU switch is a double pole isolator.
It would be preferable to have a local switch but as it has been already installed by non professionals you are a bit stuck, if the cable runs through the roof space to the shower then you may be able to insert a pull cord but it would be likely that there is not enough cable to do so and this would introduce another junction and lead to more risk.

 

[Darkwood]

It's down to interpretation but the general rule is local means so try not to find excuses to get around it .... most showers ask now for RCD protection and DP Isolation and a Rcbo does only single pole in a conventional fuse board.

 

[malcolmsanford]

You could argue the fact that the CU main switch which will be a double pole BS EN 60947-3 and so can be a device that can switch load making and breaking, gives you the manufacturers instruction on isolation. Whether you class that as "local" is a mute point.

As the guys have said there is very little you can do now unless you can rewire it into a local switch.

 

[snowhead]

Can you fit a D/pole switch at the side of the C.U?

 

[richy3333]

Can you fit a D/pole switch at the side of the C.U?

Else fit one into the ceiling at a suitable point?

 

[HandySparks]

Can you fit a D/pole switch at the side of the C.U?

Yes, I've done this where the CU was in a cupboard just outside the bathroom. You can fit a nice big reliable 45A plate switch, rather than a pull switch which is more likely to give trouble in the long term.

Still 'local' enough in my view to comply with manufacturer's instructions.

 

[Eddiesparks]

Put a switch in the CU cup'd, label it SHOWER, if a plumber can't work that out then God help us all....