Shower OPD

[RMS]

Hi,

Having a look at table 4D2A in the regs and the current carrying capacity for 6mm² ref method 4(enclosed in insulated wall) = 32A, ref method 3 conduit or trunking) = 38A, ref method 1(clipped direct) 46A.

In my experience most shower installs will fall under ref method 3 or 4 so a 6mm² cable protected by a 40amp mcb would not comply with regulations and thats before taking into account correction factors.

Is this correct as i come across a lot of 6mm² cables protected by 40amp mcbs like this?

 

[GaryMo]

I agree.

 

[equitum]

Yes, theory correct. Although most old 6mm shower installations i come accross are protected by 30A rewirable fuse.

 

[Adam_151]

You could take the view that overload protection isn't neccessary becuase the shower unit is incapable of overloading the circuit and so only short circuit and earth fault protection is neccesary, so if you do the relevant calculations and find its ok for those.

On the other hand, you could take the view that it could overload in a domestic house because a handyman could replace it with one of a higher rating (but can we really factor that in the design... he might also spur off a spur when fitting a new socket)

 

[Spark123]

For flat twin and earth, take a look at table 4D5A

 

[RMS]

For flat twin and earth, take a look at table 4D5A

My blue regs don't seem to have table 4D5A. Thanks for the comments.

 

[davy_owen_88]

For flat twin and earth, take a look at table 4D5A

My blue regs don't seem to have table 4D5A. Thanks for the comments.

Have a look here.

Page 6 shows table 4D5A.