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Topic Title: how to bypass an RCD
Topic Summary: Urgent got to do it tomorrow
Created On: 29 November 2012 09:25 PM
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 29 November 2012 09:25 PM
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Zs

Posts: 2787
Joined: 20 July 2006

Eveining, I am using you which is shameless this time. Time pressure. I need to bypass an RCD for a month and want to check this with you simply because in the time it takes to look it up everywhere I could have asked you and then done the job.

As some of you know, I actively support a charity called StreetKids direct. We help kids in Central Amercia to get off the streets and look after them. It stops them from being shot and we have our first university graduate this year which is very cool. Also one with the same name as OMS which is double cool so I will make a point of seeing that he is well supported in return for OMS's mentorship this year. Aaah.

For the month of December we have a broadcast radio station called Radio Christmas which takes over the wavelength of a local staion and also goes out on-line. Most of our fundraising is done this month.

I had my call today that the studio is at last ready to roll and have been up to have a quick look. This year, some kind soul has given us his house and he has full RCD protection. To take away all risk of nuisance tripping am going to bypass the RCD for the month. We have considerable earth leakage from the 12 Desk top computers, phone equipment and so on (we broadcast 24 hours even though during the early hours it is repeats). We go on air on 1st Dec. Aaaagh.

The bus bar is fully occupied so I cannot simply take out the RCD and shift it over a notch to a 16th Ed type set-up.

All that for this simple question:

You ok with using the RCD flexi cable as a link and moving the neutral across to the common neutral position? this leaving the RCD in a switched-off position but effectively by-passed for the month.

I'd look this up but am mashed time-wise tomorrow and will be screaming home from work, jumping in the van and turning up there with head-torch at about 9pm.

I have a couple of Sunday afternoon slots on air, gentle stuff like poetry and short stories if you want to sit back and listen. I've found a lovely old Dickens story. I'll confirm times later.

Zs
 29 November 2012 09:33 PM
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Fm

Posts: 642
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I would class this as a place of work and as such under the control of a competent person, ie you.
So no rcd required.

I would write a ms/ra to ensure that the staff report defects etc and dont use faulty equipment, more toncover you for this month, possibly supply a few rcd plug adaptors for kettles etc, or otherbhigher risi equipment
 29 November 2012 09:40 PM
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slittle

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Stick the flexi cable in the bottom of the Live terminal instead of the top and take the Neutral flexi out of the bottom and the neutral bar, and insert the one from the top of the RCD in to the neutral bar.

As FM has said, I'd cover yourself with some documentation just in case as I suspect you won't be spending all of your time there.

Or, if you've got a mainswitch handy, just swap it for the RCD for the period, that way it saves messing with the internals of the consumer unit.

Stu
 29 November 2012 09:49 PM
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OMS

Posts: 19461
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What's the earthing arrangement ?

If it is TN-S or TN-C-S, then as Stu said:

Stick the flexi cable in the bottom of the Live terminal instead of the top and take the Neutral flexi out of the bottom and the neutral bar, and insert the one from the top of the RCD in to the neutral bar.


Be bloody careful if there's no DNO isolator - get the cut out fuse out would be my advice (carefully, and look the opposite way when you do it)

Ideally, you want:

Or, if you've got a mainswitch handy, just swap it for the RCD for the period, that way it saves messing with the internals of the consumer unit.


same applies for staying safe

Regards

OMS

-------------------------
Failure is always an option
 29 November 2012 09:56 PM
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AJJewsbury

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Have you taken over the whole house, or just a room or two with the rest still occupied as a home?

I've not see it of course, while you have, but I'm slightly uneasy about removing RCD protection from an existing domestic - even if you do a full inspect & test, it's always possible that there's something nasty lurking somewhere that an RCD just might be a last line of defence against. Especially if you're imposing new, long-duration, loads the system's not used to. OK the chances are slim, but just imagine what the local paper would make of a by-passed RCD if something nasty did occur.

Could you temporarily add in an extra mini CU to power your equipment? Builder's supply-like with some suitably 'industrial' extension leads? That should avoid any possible problems with the existing installation, and even give you a point for a UPS if you really want; and you can omit-RCD (or possibly better still RCD multiple circuits separately) to your heart's content.

I'm probably being way over-cautious, it's just that having seen one or two Radio Hams' attempts electrical work, my gut reaction would be to RCD everything in sight!

- Andy.
 29 November 2012 09:56 PM
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Zs

Posts: 2787
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I've had a thought. I have an 80A main switch in the shed, if I insert that in the place of the RCD for the month? I'm hesitant because I would not normally botch something like this. I consider this to be a botch.

Thanks FM, good advice, albeit they won't get that until after launch. I'll do it. December is my alcohol-free month in case I get a call from them late at night so send chocolate and don't call me on Boxing day cos I'll be fast asleep with a glass of wine.

OMS, I owe you 200 quid for a day's work, but if you approve I have spent some of it on one-third shares in a Barcelona Football kit for a 14 year old with the same name as you in Honduras, who has never in his little life owned anything new and dreams of such a thing. Bright kid. My Mum made it thirds but it cost a packet and is the genuine article. Will you help us engineer renewables for the Manuelito Childrens' home? It is sunny out there and we want to farm the sunshine to the national grid for money, and put the kids under hot water for their first time.
Zs

Edit, thank you all, you are really quick.

TNS

Yes, main switch in the shed ( see above thoughts).

Yes, whole house Andy. Just for the month. We've built our two studios in the lounge ( rooms with glass partitions, we keep them from year to year). Using the existing sockets. I have neglected this month and should have been there more often.

What kind of covering letter? Just a statement of what I have done and for how long ok with you?

Huge thanks for prompt response. http://www.streetkidsdirect.or...t=blog&id=30&Itemid=90

Edited: 29 November 2012 at 10:31 PM by Zs
 29 November 2012 10:08 PM
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slittle

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I think I'd write some sort of method statement for them along the lines of as this is considered a place of work under the control of a skilled person, no one is to play with anything electrical but instead disturb my sleep in the event of a problem.

I'd go with the 80A mainswitch in place of the RCD (subject to a quick check as Andy has suggested) As it's a split board you can turn off the real "mainswitch" and therefore shoudn't have any issues with trying to get flexi's in or out live.

Stu
 29 November 2012 10:11 PM
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OMS

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Tell you what, cariad - I told you I wouldn't accept it before we did the job

Spend the lot - he'll have enough worries growing up there and I'm sure a few quid might help with some basic education - buy books, and he can pass them on to his buddies. Trust me - education is always the route out.

I don't know what instruments exist for selling generated electricity back, but I'll look into it - if they've got sun then solar thermal is a piece of cake for hot water - basic flat plate collectors at any efficiency will still do the job. With a bit of application, they could almost DIY it

Bit rinsed workwise at the moment, I'll sort something out and let you know next week

Best regards

OMS

-------------------------
Failure is always an option
 29 November 2012 10:12 PM
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Cremeegg

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I wouldnt bother bypassing something that might just be saving the system from something else. I'd go for a quick call to the seal fairy then a pair of Henleys; a short length of new tails usually knocking about in the van; a garage unit also probably in the van but certainly in my shed and a suitable robust set of sockets off a temporary supply for a month.

After Xmas disconnect back to garage unit and leave ready for next year.

No disturbance to existing house at all.

Good luck - we look forward to some poetry nearer Christmas.
 29 November 2012 10:16 PM
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slittle

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Originally posted by: OMS

Tell you what, cariad - I told you I wouldn't accept it before we did the job



Spend the lot - he'll have enough worries growing up there and I'm sure a few quid might help with some basic education - buy books, and he can pass them on to his buddies. Trust me - education is always the route out.



I don't know what instruments exist for selling generated electricity back, but I'll look into it - if they've got sun then solar thermal is a piece of cake for hot water - basic flat plate collectors at any efficiency will still do the job. With a bit of application, they could almost DIY it



Bit rinsed workwise at the moment, I'll sort something out and let you know next week



Best regards



OMS


I've got a great (read cheap) solution for DIY solar thermal. One of my customers heats his swimming pool with it and it cost a lot less than my "DIY solar thermal kit" on the last house. If we manage a meet around Christmas I'll explain Zs, if not you know who's got my phone number.

Stu
 29 November 2012 10:22 PM
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OMS

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If it's not black painted radiators, Stu - if you don't mind I would be interested in a knowledge share on that one.

Regards

OMS

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Failure is always an option
 29 November 2012 10:28 PM
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slittle

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Close, Black painted 15mm polypipe clipped to a black board.

I was really surprised by it but you know what farmers are like. The water is circulated by a normal danfoss DHW pump and it feeds a pool type heat exchanger to keep the two circuits apart and save the pump having pool chemicals through it.

Last time I was there on a cool but sunny day, the heat exchange was still too warm for me to hold comfortably. I'd guess at about 30m of pipe but next time I'm there I'll measure it for you.


Stu
 29 November 2012 10:33 PM
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AJJewsbury

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Sounds similar to 'bottle chopping' the bottoms off a load of glass bottles and threading a black hose pipe through them...
- Andy.
 29 November 2012 10:36 PM
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OMS

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OK Stu - cool

I guessed it was something akin to that - I rigged one up once with about 70 metres of blue alkathene, wired onto some black painted roofing sheets inside a green house - a drain back affair with a few sensors to stop pumping if there was little heat transfer going on - bloody remarkable capacity on a good day - and not bad mid season either.

I guess its the old story - why worry about the efficiency, if the input fuel is free - a friend of mine has hundreds of metres of polypipe adjacent the battens on a slate roof - not efficient, but a bloody big collector area

Regards

OMS

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Failure is always an option
 29 November 2012 10:47 PM
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OMS

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Originally posted by: AJJewsbury

Sounds similar to 'bottle chopping' the bottoms off a load of glass bottles and threading a black hose pipe through them...

- Andy.


try it with 1litre plastic pet bottles, Andy - pretty good seal and less conduction loss than glass

Regards

OMS

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Failure is always an option
 30 November 2012 05:42 PM
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PG

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Would it be possible to swap the 30mA RCD for a 100mA device?
 30 November 2012 06:20 PM
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Zs

Posts: 2787
Joined: 20 July 2006

PG, fantastic idea. Love it. Going for a rummage in the shed and on my way up there now.

Zs

Edit. Done. Main switch fitted the board best so I went for that. the homeowner signed a letter from me confirming what and why. thanks.

Edited: 30 November 2012 at 07:32 PM by Zs
 16 December 2012 12:25 PM
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Zs

Posts: 2787
Joined: 20 July 2006

If you are at your desk and have a penchant for Pink Floyd and Free, along with a bit of poetry and, well, stuff...

Radio Christmas, my show is at 2pm today. Put the kettle on and I'll read you a story.

http://radiochristmas.co.uk/

Zs
 16 December 2012 02:30 PM
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lomasjs

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Listening to your programme, nice to hear your voice Zs. You could be on Radio 4 !

-------------------------
lomasjs

Edited: 16 December 2012 at 02:51 PM by lomasjs
 16 December 2012 04:05 PM
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ebee

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Dooh,
I missed it (Only just read your post1)

Are you doing a repeat?

-------------------------
Regards,
Ebee (M I S P N)

Knotted cables cause Lumpy Lektrik
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