In-line RCD for a shower

Googleberry · 3 Nov 2009

Colleagues,

I have an 8.5kW shower wired with 15m of 6mm T&E - clipped direct and in airy conduit, a 45A DP pull-cord switch and a 40A MCB at the CU. Conventional and in all good order.

I want to install an in-line 30mA RCD outside the bathroom for extra safety ( http://nextday.diy.com/app/jsp/product/productPage.jsp?productId=90026 ). Would this be notifiable? I really can't see why it should be given that it will not in any way adversely affect the existing circuit's safety or ratings.

1john · 4 Nov 2009

it's an alteration to a circuit in a bathroom. btw, have you got an RCD tester?

Goldberg · 4 Nov 2009

Googleberry said:
I want to install an in-line 30mA RCD outside the bathroom for extra safety

Far better to replace the MCB with an RCBO, which will protect all of the cable run, not just the last part.

Googleberry · 4 Nov 2009

1john said:
it's an alteration to a circuit in a bathroom. btw, have you got an RCD tester?

No, but I can make one easily enough! Presumably it would need little more than a suitably switched 8k resistor to earth, with a means of measuring the trip time to a resolution of 1ms or thereabouts. I have lab equipment to do this very accurately, but for convenience I would probably knock-up a simple microcontroller based device to make it easier in the future. I probably wouldn't buy one!

Googleberry · 4 Nov 2009

Goldberg said:
Googleberry said:

I want to install an in-line 30mA RCD outside the bathroom for extra safety

Click to expand...

Far better to replace the MCB with an RCBO, which will protect all of the cable run, not just the last part.

Sure, and the CU will be replaced at some point; we're just not ready for that right now - an RCBO won't fit in the box. Besides, the chance of someone coming into contact with a live conductor before the shower is zero in this situation, realistically.

Goldberg · 4 Nov 2009

I've removed this misleading post.

Aragorn84 · 5 Nov 2009

How exactly? If the Live from before the RCD went thru a person to earth, the RCD would never see the current flow?

Goldberg · 5 Nov 2009

Aragorn84 said:
How exactly? If the Live from before the RCD went thru a person to earth, the RCD would never see the current flow?

You're quite right. I had some bad news last night and it looks like I wasn't thinking clearly when I posted that.

sparkwright · 5 Nov 2009

Googleberry said:
Goldberg said:

Googleberry said:

I want to install an in-line 30mA RCD outside the bathroom for extra safety

Click to expand...

Far better to replace the MCB with an RCBO, which will protect all of the cable run, not just the last part.

Click to expand...

Sure, and the CU will be replaced at some point; we're just not ready for that right now - an RCBO won't fit in the box. Besides, the chance of someone coming into contact with a live conductor before the shower is zero in this situation, realistically.

don't fit the in-line RCD just outside the bathroom, fit it next to the CU.

it will then be an easy task when you do get the CU replaced, and you then won't have to worry about that in-line RCD.

ban-all-sheds · 5 Nov 2009

Googleberry said:
Would this be notifiable?

Absolutely everything is notifiable unless it's listed in Schedule 2B as non-notifiable.

Since adding an RCD is not listed, it is notifiable.

I really can't see why it should be given that it will not in any way adversely affect the existing circuit's safety or ratings.

Nevertheless....

Googleberry · 5 Nov 2009

sparkwright said:
Googleberry said:

Goldberg said:

Googleberry said:

I want to install an in-line 30mA RCD outside the bathroom for extra safety

Click to expand...

Far better to replace the MCB with an RCBO, which will protect all of the cable run, not just the last part.

Click to expand...

Sure, and the CU will be replaced at some point; we're just not ready for that right now - an RCBO won't fit in the box. Besides, the chance of someone coming into contact with a live conductor before the shower is zero in this situation, realistically.

Click to expand...

don't fit the in-line RCD just outside the bathroom, fit it next to the CU.

it will then be an easy task when you do get the CU replaced, and you then won't have to worry about that in-line RCD.

Good idea.

Googleberry · 6 Nov 2009

ban-all-sheds said:
Googleberry said:

Would this be notifiable?

Click to expand...

Absolutely everything is notifiable unless it's listed in Schedule 2B as non-notifiable.

Since adding an RCD is not listed, it is notifiable.

I really can't see why it should be given that it will not in any way adversely affect the existing circuit's safety or ratings.

Click to expand...

Nevertheless....

Then again...

kai · 6 Nov 2009

Thinking about it, why can't an RCD in a small din-mount housing, be fitted outside the bathroom door, serving as a substitute for the pull cord switch inside the bathroom?
As long as the RCD is designed with "Switching duty" in mind, (which of course is the case if it was intended for fitting as a mainswitch to a consumer unit), it can safely double up as a shower isolator, as it will get used regularly, lessening the risk of any sticking of the works,

RF Lighting · 6 Nov 2009

Because it'll look rubbish

ban-all-sheds · 6 Nov 2009

Googleberry said:
Then again...

Then again what?

It is notifiable, no matter how ridiculous you think that is.

Your question was:

Googleberry said:
Would this be notifiable?

and the answer is yes, it would be - there is absolutely no doubt about that.

I really can't see why it should be given that it will not in any way adversely affect the existing circuit's safety or ratings.

Maybe you can't but your inability to see why it should be does not change the fact that it is.

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In-line RCD for a shower

Goldberg

Goldberg

Goldberg

kai

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