Special Needs and the RCD

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beemer

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According to the new directive (17th Edition), most new circuits need to be additionally protected by a RCD or RCBO, but what about people with special needs? For example:

We are due to start an extension to a house for an adult with very special needs.

A sub board will provide his electrical needs for lighting, power circuits and shower. He needs an electrical respirator during the night when he is sleeping, but I can't put that particular socket that runs his respirator on a circuit that might switch it's self off during the night!

O.K. I hear you say, have a dedicated socket, on the non RCD side of the board, neatly labelled. The problem is he will decide where his bed is going to go once the extension has been completed! I have the same problem (albeit no so life threatening) with the location of his TV aerial point!

Have I missed something in the 'book' that will allow for this situation or is he doomed? :|

 
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In all honestly Iwould think that the bed could only be put in a couple of locations, so put a couple of dedicated sockets in.. remember that although you do not have to RCD the socket you will still have to RCD the cable if it is burried <50mm without any mechanical protection.

Same with the TV (re number of locations) bang a couple of outlets in!!

 

Lec

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As above^, any distance form the sockets can be done with an extension /trailing lead.

 

TTbangbang

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I hope he has a back up generator or summat - we're heading for more brownouts and power outages if you believe the news reports. :(

 

dean mac

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I hope he has a back up generator or summat - we're heading for more brownouts and power outages if you believe the news reports. :(
why not put the dedicated sockets in surface trunking no need for rcd then

 
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If I were doing the job I'd do it to the 16 th edition and sod 'em . The guy' s life comes first, he has enough to cope with without an RCD tripping out his respirator.

There would have been no problem a few months ago so why do we dig ourselves a hole to climb into .

If someone comes along and says you have done the wrong thing tell 'em they can take the responsibility and fit an RCD .

Record what you have done on your cert. SOMETIMES COMMON SENSE SHOULD PREVAIL.

Deke

 

steptoe

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sod them all, DEVIATE, thats what the box is there for.

SPECIAL CIRCUMSTANCES, you dont have to stick to the guide.

put a nice bright shiny label by the consumer unit stating that

NO WORK OF ANY KIND SHALL BE CARRIED OUT IN THIS DWELLING WITHOUT PRIOR INSTRUCTION FROM THE DESIGNER(or designated person)

or some such bumf, and make it clear on your cert too the reasons for the deviation, you could also provide additional sheets showing positions of cables etc(to the designer, or designated person)

dunno how you feel about it, I suppose its all down to your own confidence about not following a guide book.

 
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I would assume this comes under 131.7

Protection against power supply interruption.

Where danger or damage is expected to arise due to an interruption of supply, suitable provision shall be made in the installation or installed equipment.

Allows for suitable alternative arrangements? :|

.....A sub board will provide his electrical needs for lighting, power circuits and shower. He needs an electrical respirator during the night when he is sleeping, but I can't put that particular socket that runs his respirator on a circuit that might switch it's self off during the night!

O.K. I hear you say, have a dedicated socket, on the non RCD side of the board, neatly labelled. The problem is he will decide where his bed is going to go once the extension has been completed! I have the same problem (albeit no so life threatening) with the location of his TV aerial point!

Have I missed something in the 'book' that will allow for this situation or is he doomed?
How about running all cables in surface, trunking / conduit / dado or skirting trunking? so No protection required for cables.

Put all other sockets on as RCD socket outlets,

bar the one needed to be Non-RCD..

If the bed moves go and swap an RCD socket with a non RCD socket? :) ;)

 

beemer

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Thanks for ideas, I need to investigate if the respirator would have a power failure alarm. I would have thought so, especially as 'he' would be in the extension on his own!

Surface trunking would look awful even though it may have been the way to go, and also as it is a ground floor dwelling, so sockets could possibly be used to power things outdoors.

Not so keen on having to justify my design in a court of law, or be responsible for his demise. :|

All cables have been first fixed now, plasterer is in, so it's down to CU board choice :)

 

mikel

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wouldn't be surprised if its got a battery back up. Especially if you consider what would happen if there was a power failure!

 
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wouldn't be surprised if its got a battery back up. Especially if you consider what would happen if there was a power failure!
hmmm? :| ?:| indeed!

how much power does this respirator use?

I am thinking that if chair lifts & bath chairs... which are using motors to move the whole body wieght... cant a respirator have batter back-up..

e.g. allow 24hrs of power off? :|

 
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I'm a little confused by the medical device. A respirator is used on a patient either in a coma (part of a life support machine) or under general anaesthetic. It is connected to a tube into the windpipe (endo-tracheal tube). It breathes for the patient pumping air into the lungs.

People with asthma have nebulisers - a device that forms a fine mist of a certian drug.

Some people with respiratory problems have supplimental oxygen, the most economical way is an oxygen generator. A device that plugs in and concentrates the oxygen in the air from 21% upto 95% and can deliver between 7-10 litres per minute. The 'back-up' for one of these is an oxygen cylinder. They don't use excessive ammounts of power.

I can't imagine a patient would be sent home on a respirator in the true sense of the term!

 
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This is a special situation, so your design would reflect this. As I said above I would most definately not include an RCD, ( you would'nt have 6 months ago would you ?) its not outside, its not a bathroom. In fact I would also fit HRC fuses to reduce the risk of tripping out. If a lamp blows in the night it will no doubt , trip a 6amp MCB ! Put the guy in the dark. It won't blow a 10 amp BS 88 fuse. Why don't you ask your Part P provider and listen to them avoid the issue and drop it back in your lap.

As an after thought , I'd run each socket on a radial which would reduce the risk even more.

If you had to justify this in a court of law the outcome would be that you had done everything possible to reduce any risk of power outage.

The regs are not mandatory as far as I know.

Deke

 

steptoe

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This is a special situation, so your design would reflect this. As I said above I would most definately not include an RCD, ( you would'nt have 6 months ago would you ?) its not outside, its not a bathroom. In fact I would also fit HRC fuses to reduce the risk of tripping out. If a lamp blows in the night it will no doubt , trip a 6amp MCB ! Put the guy in the dark. It won't blow a 10 amp BS 88 fuse. Why don't you ask your Part P provider and listen to them avoid the issue and drop it back in your lap.As an after thought , I'd run each socket on a radial which would reduce the risk even more.

If you had to justify this in a court of law the outcome would be that you had done everything possible to reduce any risk of power outage.

The regs are not mandatory as far as I know.

Deke
very true, I like you, :D

put a little label on the sockets,

'NOT FOR OUTDOOR USE'

I honestly think your best path is a deviation from the regs, and NO RCD protection, if you do everything else to the regs and show on your cert that its a deviation then your provider will be as liable as you for accepting it,

just prove your <50v touch and you will be fine,

if you are that worried and can provide me with a day on the beer with a night in a lap dancing club then I'll come and do your test&insp and sort out your certs for you.....

 

beemer

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Thanks again for all your replies.....

Have decided to go for a mix of MCBs and RCBO's.

I have included a dedicated MCB on a radial circuit for the respirator that the guy needs when he sleeps, but I have it coiled up in the roof space ready to feed it to a dedicated socket appropriately labelled (see! I do listen to you), it will run down the wall in trunking, once the location has been finalised.

Smokes will be on a MCB and the rest..shower,lights,sockets will be via RCBO's.

;)

 
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