Electrical advice, please.

Bronnie

I am having an electrician round to put do a small job on my oven, but also to fit a new bathroom light for me which I am supplying. The light is suitable for zone 2 and the instructions say;

When fitting in a bathroom a 30mA RCD must be used

I have an electric shower and had the whole-house electrics overhauled in 2008 when I bought the house. Am I right to assume there will already be a 30mA RCD installed, does it cover all installations in the room? I am not really sure where to look on the Electrical Cert or will it be visible in the meter cupboard?

Want to make sure the job can be done on the day in one visit to keep costs down.

Thank you.

YorkshireBoy

Any RCD/RCBO fitted will be in the consumer unit, along with the rest of your MCBs.

Bronnie

erm............

the consumer unit was new in Nov 2008. It has 6 switches all labelled for different parts of the installation, then to the right, under a sticker saying "Main Switch", there is a switch that says CDC263U and a blue Test Button that says 63A/.....

There is a manufacturer's sticker on the casing saying
"This installation, or part of it is protected by a device which automatically switches off the supply if an earth fault develops"

Thank you.

Myser

Bronnie - Does it look like your fuse box is split in two halves i.e. the circuit breakers are banked with a gap in the middle?

That would indicate that only half of the board is RCD protected.

The CDC263U is a Hager RCD which is very reliable:

http://www.electricalstock.com/webapp/wcs/stores/servlet/product_10751_164_36189_-1_hager-cdc263u-rccb-dp-63a-30ma

You are supposed to press the blue button every so often to check that the RCD is working correctly. Note, that this will turn off the power to all the connected circuits (sockets and lights). To reset, just pull the lever back up.

If when you press the blue button, the bathroom light turns off, it is protected by the 30mA breaker.

Bronnie

Hi, thanks for replies.

the circuit breakers and the main switch are all lined up close together .......no gaps between them.

so that main switch on the right the RCD ? Should be no issues when he comes to install the bathroom light then?

Myser

It seems like all circuits are protected by the same RCD. This doesn't comply with the current 17th edition regulations. As if there is a fault on an individual circuit, the RCD trips and all the circuits in the house are powered down.

You can confirm if the bathroom light is powered by the RCD. Switch it on and then press the blue test button. If the light goes out, it is protected by the RCD.

Note that if all circuits are powered via the RCD, you may need to reset clocks on appliances if they don't have a battery backup.

As I mentioned in my previous post, you should be testing the RCD periodically.

The link in my previous post shows the RCD.

The main switch is separate to this - it should be labelled.

Bronnie

Myser wrote: »

It seems like all circuits are protected by the same RCD. This doesn't comply with the current 17th edition regulations. As if there is a fault on an individual circuit, the RCD trips and all the circuits in the house are powered down.

You can confirm if the bathroom light is powered by the RCD. Switch it on and then press the blue test button. If the light goes out, it is protected by the RCD.


Note that if all circuits are powered via the RCD, you may need to reset clocks on appliances if they don't have a battery backup.

As I mentioned in my previous post, you should be testing the RCD periodically.

The link in my previous post shows the RCD.

The main switch is separate to this - it should be labelled.

Bathroom light and shower power-light went off when I pressed the TEST button, as did rest of house.

There doesn't seem to be another Main Switch anywhere though?? There is a printed sticker above the Test Button unit that says Main Switch??

The electrician coming on Tuesday is from a reputable local appliance repairs company (not the electrician who issued the 2008 cert). Just that I like to have a bit of advance info so I'm not blinded with science.

Does compliancy with current regs just refer to new electrical installations?

Myser

OK, so you have confirmed that the bathroom and all electrics are protected by an RCD.

It is possible that the RCD is your main isolation switch but this is unusual. Has another isolator switch been placed outside the fuse box - perhaps near the meter?

Given the configuration of your fuse box with all circuits protected by the same RCD, the electrician may recommend updating it to be compliant with 17th edition regulations. Compliancy only refers to new installations however, if he/she is installing a new oven or shower for instance, they may need to put it on a separate fusebox or RCBO (combined RCD and circuit-breaker).

Partly the reason for the 17th edition regulations is to prevent nuisance tripping. You don't want a blown light bulb plunging the whole house into darkness or switching off all circuits. In a fuse box that is 17th edition compliant, there will usually be two banks of circuit-breakers protected by two separate RCDs or each circuit is protected by a separate RCBO.

If you are interested in reading more about the 17th edition changes, have a read of this useful guide by Hager:

http://www.tlc-direct.co.uk/Technical/DataSheets/Hager/Hager_17.pdf

Bronnie

Have had a good look, but definitely no other mains switch there or in the meter cupboard next to it.

Thanks for the heads-up anyway, appreciate your time and advice.

Don't know what I'd do without the patient responses from this board.........as no one else to ask and reluctant to go to the professionals without a bit of insider info first :beer: