RCD and Split supply

[coshhassessor]

I've got a TT supply to my consumer unit, which (naturally) has an RCD on board. So far so good. Now, are ALL the MCBs connected via the RCD as a matter of course, or could it be a split load system (as I've had in the past)? If it is split, how can I find out what does and does not have RCD protection.

"Normal" methods I've thought of that won't work include: look at the circuit diagram (there isn't one), call the installing spark (he's dead) call the compnay he worked for (wound up). Therefore, it looks like an "engineering solution".

Advice please!

COSHH

 

[HDRW]

First, if it's TT then everything *should* be RCD protected...

If the Consumer Unit is split-load, there will be an RCD and a Double Pole Disconnector switch (usually rated 100A) in the CU. Usually the RCD will be somewhere in the middle, and the Disconnector at one end. The MCBs between the two are not RCD protected, the ones beyond the RCD are.

If the unit isn't split-load, you won't have the Disconnector, and the RCD will be at one end.

There's also the possibility that the RCD and Disconnector are at either end - this is split but with no easy way to see what the RCD protects unless it's labelled properly - ask again if this is the case!

The upshot, though is that if there is only an RCD then everything is protected by it.

Cheers,

Howard (not a professional spark but an experienced DIYer!)[/b]

 

[comms]

On a TT system the whole board should be protected by a time delay dp RCD main switch rated at 100amp 100mA (with correct label stating rcd main switch), this rcd will protect circuits to lights , cooker , water heater , smoke detectors/alarms

Then a second RCD 30mA is used this will cover the socket outlets that can supply portable equipment outdoors & any portable equipment that is outdoors. ( most tend to put all socket outlet circuits to the 30mA rcd any way)

If you don't want to go delving inside the cu to find out what circuits are protected by it, why not just push the test button on the rcd & see what circuits go off around the house( my guess is only the socket outlets will go off)

 

[comms]

Just had a thought you may have an ordinary double pole 100amp main switch then the circuits could be protected by RCBO's;
cooker , water heater , smoke alarms all on 100mA rcbo's
socket outlet circuits, showers on 30mA rcbo's

 

[securespark]

If you have one or more iso's, switch 'em off then see what stops working - SIMPLE!!