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Topic Title: Enclosures.
Topic Summary: Fire.
Created On: 09 July 2018 01:45 PM
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 09 July 2018 01:45 PM
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Zoomup

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Arternoon all,
If I wanted to use an insulated enclosure to house an upfront R.C.D. before an amendment 3 consumer unit in a TT earthed installation would Reg. 421.1.6 prevent me from doing so? Sorry if this has been discussed before but these days I have the memory of a goldfish.

Z.
 09 July 2018 01:57 PM
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dustydazzler

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Just do it
 09 July 2018 02:08 PM
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AJJewsbury

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If I wanted to use an insulated enclosure to house an upfront R.C.D. before an amendment 3 consumer unit in a TT earthed installation would Reg. 421.1.6 prevent me from doing so?

Provided the enclosure complies with an appropriate product standard (which I suspect will include a traditional glow wire test, like the old plastic CUs were meant to pass), it'll be fine; otherwise the 2nd paragraph suggests it only has to be good for maximum normal operating temperature (70 degrees?)

- Andy.
 09 July 2018 02:15 PM
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Zoomup

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But wouldn't that product standard reqirement have to be as robust as having a metal enclosure? What insulated enclosure meets that product standard requirement?

Z.
 09 July 2018 02:37 PM
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gkenyon

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Originally posted by: Zoomup

Arternoon all,

If I wanted to use an insulated enclosure to house an upfront R.C.D. before an amendment 3 consumer unit in a TT earthed installation would Reg. 421.1.6 prevent me from doing so? Sorry if this has been discussed before but these days I have the memory of a goldfish.



Z.
421.1.201 might ... if it's in a dwelling ... because it's switchgear as defined in Part 2.

For those wanting to revive the "it's not switchgear" argument, see 536.4.201 in BS 7671:2018, the first para of which answers this question once and for all on what this assembly could be ... and the rest of the Reg effectively states "got to be the right box for the RCD, as tested by the manufacturer, or you're responsible for the assembly" ... including ratings to meet 536.4.201.

536.4.201-536.4.203 may be new to BS 7671, but they are just stating the product situation that's been in place for a long time re- whether the assembly is the installer's responsibility or the manufacturer's.

-------------------------
EUR ING Graham Kenyon CEng MIET TechIOSH
G Kenyon Technology Ltd

Web-Site: www.gkenyontech.com
 09 July 2018 02:45 PM
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gkenyon

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Originally posted by: AJJewsbury

If I wanted to use an insulated enclosure to house an upfront R.C.D. before an amendment 3 consumer unit in a TT earthed installation would Reg. 421.1.6 prevent me from doing so?


Provided the enclosure complies with an appropriate product standard (which I suspect will include a traditional glow wire test, like the old plastic CUs were meant to pass), it'll be fine; otherwise the 2nd paragraph suggests it only has to be good for maximum normal operating temperature (70 degrees?)



- Andy.
But see 536.4.201 to 536.4.203 in the 18th Edition before you decide to "make your own" from RCD + Box, and your responsibilities to comply with the relevant standards for safety (BS EN 61439-series), and also how this impacts the decision on whether it's a swtichgear assembly or not if it's a dwelling (and therefore would have to be metal if it were a switchgear, controlgear or similar assembly).

-------------------------
EUR ING Graham Kenyon CEng MIET TechIOSH
G Kenyon Technology Ltd

Web-Site: www.gkenyontech.com
 09 July 2018 02:46 PM
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gkenyon

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Originally posted by: Zoomup

But wouldn't that product standard reqirement have to be as robust as having a metal enclosure? What insulated enclosure meets that product standard requirement?



Z.
Question for the suppliers

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EUR ING Graham Kenyon CEng MIET TechIOSH
G Kenyon Technology Ltd

Web-Site: www.gkenyontech.com
 09 July 2018 02:46 PM
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gkenyon

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Originally posted by: dustydazzler

Just do it
Perhaps not?

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EUR ING Graham Kenyon CEng MIET TechIOSH
G Kenyon Technology Ltd

Web-Site: www.gkenyontech.com
 09 July 2018 02:47 PM
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dustydazzler

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Originally posted by: gkenyon

Originally posted by: dustydazzler



Just do it
Perhaps not?


Why not ?
 09 July 2018 02:58 PM
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OMS

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Originally posted by: dustydazzler

Originally posted by: gkenyon



Originally posted by: dustydazzler


Just do it
Perhaps not?


Why not ?


Because Nike don't make RCD enclosures ?

And Frankie said, don't do it

Regards

OMS

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Let the wind blow you, across a big floor.
 09 July 2018 03:11 PM
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AJJewsbury

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But see 536.4.201 to 536.4.203 in the 18th Edition before you decide

As my copy of the 18th still hasn't arrived, I'm still on the 17th!! (as I presumed the question was)

What's the 18th equivalent of 531.4.1? (the bit requiring the use of Class II equipment between the origin and the RCD)

- Andy.
 09 July 2018 03:49 PM
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gkenyon

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Originally posted by: AJJewsbury

But see 536.4.201 to 536.4.203 in the 18th Edition before you decide


As my copy of the 18th still hasn't arrived, I'm still on the 17th!! (as I presumed the question was)



What's the 18th equivalent of 531.4.1? (the bit requiring the use of Class II equipment between the origin and the RCD)



- Andy.
To the best of my knowledge, 531.3.5.3.2.201, but it's not worded in the same way, the Class II now double or reinforced insulation and limited to the live conductors only (incoming cables, extension terminals, etc.), and insulated and non-metallic sheathed cables are deemed to meet the requirement.

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EUR ING Graham Kenyon CEng MIET TechIOSH
G Kenyon Technology Ltd

Web-Site: www.gkenyontech.com
 09 July 2018 03:51 PM
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gkenyon

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Originally posted by: dustydazzler

Originally posted by: gkenyon



Originally posted by: dustydazzler







Just do it
Perhaps not?




Why not ?
See previous post 09 July 2018 02:45 PM

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EUR ING Graham Kenyon CEng MIET TechIOSH
G Kenyon Technology Ltd

Web-Site: www.gkenyontech.com
 09 July 2018 04:30 PM
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chrispearson

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As I read the 18th, standard insulated and sheathed consumer tails between the meter and main switch are compliant. If, however, the main switch does not incorporate an RCD, e.g. an all RCBO board, the notes to 531.3.5.3.2.201 suggest that the internal cables (line and neutral) need to be more durable than they have been.

Incidentally, Wylex will sell you a two-pole S type RCD in a REC2 enclosure, whch seems to address the OP and subsequent discussion above.
 09 July 2018 04:34 PM
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Zoomup

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18th. 531.3.5.3.2.201.

"For Class I enclosures in TT systems where RCD protection is used on outgoing circuits, double or reinforced insulation of all live conductors (incoming cables, extension terminals, etc.) on the supply side of the incoming device, e.g. main switch, shall be used. Insulated and non-metallic sheathed cables are deemed to meet the requirements of double or reinforced insulation".


NOTE 1. When selecting equipment, consideration should be given to the assembly manufacturer's internal line interconnecting cable links on the supply side of an RCD being insulated and not metallic sheathed, or having reinforced insulation or equivalent mechanical protection.

NOTE 2. Only the assembly manufacturer's approved internal interconnecting cable links should be used.

Z.

Edited: 09 July 2018 at 04:42 PM by Zoomup
 09 July 2018 04:45 PM
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Zoomup

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Where can I buy an Amendment 3 all insulated enclosure for an R.C.D. or one already made up that complies, for TT use please?

Z.
 09 July 2018 06:12 PM
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chrispearson

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Originally posted by: chrispearson

Wylex will sell you a two-pole S type RCD in a REC2 enclosure, whch seems to address the OP and subsequent discussion above.

Originally posted by: Zoomup

Where can I buy an Amendment 3 all insulated enclosure for an R.C.D. or one already made up that complies, for TT use please?


This was Wylex's response to my query:

Are 100 mA type S RCDs available in enclosures such as the REC2 please? I need to put an RCD at the origin of a TT installation and it seems sensible to isolate the downstream equipment using an RCD rather than a linked main switch.

You can order the RCD and enclosure separately part numbers would be RCD WRMT100/2 and REC2s enclosure ESi2S

HTH
 09 July 2018 06:33 PM
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sparkingchip

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Another all encompassing regulation that depending on how it is applied causes more issues than it resolves.

Only ten minutes ago on my way home I called in at a house that has a rewirable fuse board with an oboslete upfront VOELCB that could be replaced with an upfront 30 mA RCD in a REC plastic enclosure significantly increasing the safety of the installation.

There are millions of homes like that in the UK where the homeowner's cannot afford to spend much money on improving their electrical installation and no financial support is available.

The 18th tinker with the issues caused by using a metal enclosure by saying the tails need beefing up, when I stated that enclosing tails in plastic trunking as supplementary protection is a way to run longer tails upstream of the RCD some forum members said it is rough as a badgers bottom, yet isn't that what the 18th edition is pointing us towards again?

Andy B.
 09 July 2018 06:40 PM
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AJJewsbury

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Where can I buy an Amendment 3 all insulated enclosure for an R.C.D. or one already made up that complies, for TT use please?

Wylex also seem to have an S-type RCD in a REC2 enclosure in their 2018 catalogue - http://www.wylexreasons.co.uk/...logue%20Feb%202018.pdf - their page 18 (physical page 20). Oddly it doesn't have a product code, but as neither do many of the new AFDD products, I suspect it's just due to it being new rather than anything untoward.
- Andy.
 09 July 2018 06:56 PM
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Zoomup

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I think that things are getting just too silly and complicated. I shall buy a REC2 and chuck the 100 Amp D.P. switch away and fit my own S type 100mA R.C.D. inside. I will install this upstream of any consumer units with TT earthing. As no internal single insulated tails are involved all will be well and the enclosure is all insulated. That is the cost effective way for me. If the energy metering people/energy distributors use REC2s then so can I.

Z.
IET » Wiring and the regulations » Enclosures.

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