Clarification Needed

[Power Ball]

As a Part P electrician when I am asked to change a CU for a domestic customer I always put in a split load 2x rcd in however many ways I need plus spares.

Just looking through some electric mags and see that they still offer CU's Split Load 1 Main switch covering as many ways X 1 RCD covering as many ways. ( why would you use this combination)

( Am I right in thinking the main switch would cover any RCBO's you were using )

Or 100amp rcd as the main switch ( why would you use this combination)

Thanks

Chas

 

[ianmacd]

If you are using RCBO's. RCD main switch, not much use unless its time delayed.

 

[SPECIAL LOCATION]

As a Part P electrician when I am asked to change a CU for a domestic customer I always put in a split load 2x rcd in however many ways I need plus spares.Just looking through some electric mags and see that they still offer CU's Split Load 1 Main switch covering as many ways X 1 RCD covering as many ways. ( why would you use this combination)

( Am I right in thinking the main switch would cover any RCBO's you were using )

Or 100amp rcd as the main switch ( why would you use this combination)

Thanks

Chas

Although the normal 90%+ of domestic jobs are bog standard T&E sunk in plaster less than 50mm from surface....

It is feasible on some of the less standard type of property to install circuits that do not need RCD protection....

Surface mounted / Run in metal conduit / Downstairs lighting / Fixed heating appliance via FCU etc...

Some older properties do not easily allow concealing of cables..

may be more of a proper neat surface job required....

or may require additional fire retardant properties with use of MICC..

Then of course you have numerous light commercial applications / where a number of non-RCD circuits are perfectly permitted within the regs!

So there can be many applications where the older standard split-load board may be used..

100A RCD main switch may be used on a TT with some circuits not needing 30ma protection:-

running surface, lights, cooker, immersion heater (not in bathroom)..?

You have to think outside of the average housing estate with loadsa semi-detached, plaster board walls walls!

:coffee

 

[ianmacd]

Run in Earthed metal conduit100A RCD main switch may be used on a TT with some circuits not needing 30ma protection:-

running surface, lights, cooker, immersion heater (not in bathroom)..?

:coffee

Unless main switch is TD will not provide discrimination from rcbo.

 

[SPECIAL LOCATION]

Run in Earthed metal conduit

erm yep... as in relation to my post, the metal conduit WOULD be and exposed conductive part!!! :|

Unless main switch is TD will not provide discrimination from rcbo.

Sybil Fawlty; specialist subject "stating the bleeding obvious", come to mind!!!

:|

:C

As the OP does refer to "looking through some electric mags" and questioning why various manufactures still offer a 100ma main switch option,

I had assumed that this was referring to Time Delayed!!!! and had taken it as read, this was in relation to bog standard TT configuration prior to 17th ed...

such as the configuration illustrated in fig 3.2 in OSG pg 24.

Whereby discrimination has NO issues with the circuits NOT NEEDING 30ma protection...

Just like wot I rote befouyr!!!! :innocent

100A RCD main switch may be used on a TT with some circuits not needing 30ma protection:-running surface, lights, cooker, immersion heater (not in bathroom)..?

But you are strictly correct in your statement Ian, I am now going to sit on the naughty step for the rest of the night.

I would however be interested to see ANY manufactures literature showing a split load board with a 100ma RCD main switch that ISN'T already a time delayed device....

I don't think I have seen a "100ma Non Time Delayed" standard CU configuration offered?

:|