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Topic Title: selv in a commercial wetroom
Topic Summary: is rcd required
Created On: 14 April 2009 02:14 PM
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 14 April 2009 02:14 PM
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tillie

Posts: 937
Joined: 03 May 2006

Hi I installed 10 x selv spotlights in a wetroom over the weekend.

I used an existing lighting cct which I diverted to a klik 10 way distribution unit.

Now this unit is above an access panel in the corner of the room outside zones 1 and 2.

Does the circuit need rcd protection when the 230v supply in my opinion is outside the room and all that can be seen are the class 3 light fittings.

Also not that I think this has any bearing but all pipework is plastic and the underfloor heatng is rcd protected.

Advice please

Regards
 14 April 2009 03:22 PM
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GeoffBlackwell

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Joined: 18 January 2003

Read 701.32.1 last sentence.

Edit - I am assuming that this wet room is within the scope of Section 701 - it might not be if it is commercial.

Regards

Geoff Blackwell

Edited: 14 April 2009 at 03:55 PM by GeoffBlackwell
 15 April 2009 01:05 AM
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spinlondon

Posts: 5494
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I thought the Regs stated that all circuits in the Bathroom must be protected by an RCD?
Are you saying that you have placed a DB in zone 3 of a Bathroom?

Edited: 15 April 2009 at 01:05 AM by spinlondon
 15 April 2009 02:08 AM
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micjamesq

Posts: 777
Joined: 23 January 2009

Originally posted by: spinlondon

I thought the Regs stated that all circuits in the Bathroom must be protected by an RCD?

Are you saying that you have placed a DB in zone 3 of a Bathroom?

More of a lighting distribution system spin:

Lighting Distribution System Equipment

Regards

-------------------------
E & OE
 15 April 2009 02:24 PM
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tillie

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Hi ,Thank you micjamesq that is exactly what I used.

The distribution box is mounted a foot above the wetroom ceiling through an access panel.

If I was to compare this to a domestic setting then if I was to install 10 x 12v lights and located the transformers in the loft would the circuit still need rcd protection.

ie does the 230v supply for selv lighting need to be rcd protected even though only the class 3 lights are visible and outside zones 1 and 2 ( no longer zone 3 ).

Regards
 15 April 2009 02:48 PM
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OMS

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How is the marshalling box switched ?

OMS

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Let the wind blow you, across a big floor.
 15 April 2009 03:00 PM
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GeoffBlackwell

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I assume the lights are in zone 2.

701.411.3.3 calls for additional protection as defined in 415.1. This protection is specified to enhance both the basic and fault protection of the circuit. It is also supposed to provide some protection against carelessness by the users.

The fact that your fittings are class III is not relevant - the protection is for the circuit and this includes the section in the ceiling void. This is specifically stated in the last sentence of 701.32.1. Your connections from the Klix unit to each fitting are doubtless in flex, and unless you have taken measures to prevent it, this flex maybe on or close to the ceiling surface.

In any event if your wet room falls within the scope of Section 701 you have a problem.

Regards

Geoff Blackwell
 15 April 2009 03:03 PM
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OMS

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but put simply, if the switch is in the room (not necessarily in Zone) then RCD protection is required anyway - ie all circuits of the location

OMS

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Let the wind blow you, across a big floor.
 15 April 2009 04:26 PM
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Jaymack

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If you have not installed new cables in walls; and only in the ceiling cavity outwith the zones, I'd say that RCD protection is not required, moreso as this is a commercial installation as you state.
It's not major cost in any case to install a replacement RCBO for the existing MCB - not something I would do though. Bounce it off your fundsucker, if you have one.

Regards
 15 April 2009 04:43 PM
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OMS

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Not sure this has anything to do with concealed cables - the requirement is for all circuits of the location - and the OP has clearly modified that circuit so an RCD is required

Regards

OMS

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Let the wind blow you, across a big floor.
 15 April 2009 04:47 PM
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GeoffBlackwell

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The scope of section 701 does not exclude commercial locations it excludes emergency facilities. If this location is not in the exclusions it must comply with Section 701.

701.411.3.3 calls for additional protection as defined in 415.1. This protection is specified to enhance both the basic and fault protection of the circuit. It is also supposed to provide some protection against carelessness by the users.

The wording of this regulation is perfectly clear - additional protection shall be provided for all circuits of the location. This wording has a side effect in that it would include the selv circuits but that is not the issue here - rather it is the supply circuits to the selv units that are in question.


Regards

Geoff Blackwell

Edited: 15 April 2009 at 04:48 PM by GeoffBlackwell
 16 April 2009 01:45 PM
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AJJewsbury

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The wording of this regulation is perfectly clear - additional protection shall be provided for all circuits of the location. This wording has a side effect in that it would include the selv circuits but that is not the issue here - rather it is the supply circuits to the selv units that are in question.


The distribution box is mounted a foot above the wetroom ceiling through an access panel.


If the transformers are also above the ceiling, then surely it's only the SELV circuits that actually enter the location (presuming the switching is also outside). Isn't the secondary a separate circuit from the primary (I think we wouldn't expect the MCB to trip if the secondary was overloaded, but for the transformer to provide it's own overcurrent protection to the secondary).

If so, why would the supply circuit need RCD protection under 701.411.3.3?

- Andy.
 16 April 2009 01:53 PM
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GeoffBlackwell

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My understanding is that these are SELV fittings i.e. light and transformer in one.

The circuit between the Klik unit and the fitting is therefore not SELV. I accept that whilst the text in BS 7671 actually applies to SELV circuits this is not intended and will be corrected.

Given the words in the last sentence of 701.32.1 I don't see how you can doubt that BS 7671 requires RCD protection.

I am not saying that I think it is a good or bad thing - I am just indicating what the regulations say.


Regards

Geoff Blackwell

Edited: 16 April 2009 at 01:54 PM by GeoffBlackwell
 16 April 2009 02:04 PM
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AJJewsbury

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If the light fittings accept 230V then I agree entirely - the LV circuit enters the location. I'd presumed from the description that the fittings were class 3, that they took a SELV supply and hence had a separate transformer - perhaps tillie could clarify?

- Andy.
 16 April 2009 02:07 PM
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OMS

Posts: 22864
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If that is true Andy then Tillie appears to be using the marshalling box on SELV - don't know what that does for the current rating of the terminal pin contacts etc.

Regards

OMS

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Let the wind blow you, across a big floor.
 16 April 2009 02:33 PM
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AJJewsbury

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Ah, yet another possibility! I'd imagined the distribution box was operating at 230V, feeding multiple transformers (above the ceiling), each feeding a single class 3 fitting.

- Andy.
 16 April 2009 07:37 PM
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aligarjon

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Originally posted by: AJJewsbury

Ah, yet another possibility! I'd imagined the distribution box was operating at 230V, feeding multiple transformers (above the ceiling), each feeding a single class 3 fitting.



- Andy.


This is how i read it Andy,feeding individual transformers. if that is the case i don't think an rcd is required,presuming the switch is outside the door. Also is there an extractor linked in somewhere,or is that the in-line type in which case no problem. Gary

-------------------------
Specialised Subject. The Bleedin Obvious. John Cleese
 16 April 2009 09:00 PM
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spinlondon

Posts: 5494
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Originally posted by: OMS
but put simply, if the switch is in the room (not necessarily in Zone) then RCD protection is required anyway - ie all circuits of the location

OMS


My understanding is that Zone 3 is no longer defined. As in it now extends from zone 2 to the walls and ceiling of the room.
 16 April 2009 09:13 PM
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spinlondon

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This is really weird, I know that some of the Regs. are very ambigious, but this is one of the rare ones that's very clear.
The Reg. requires all circuits in a bathroom to be protected by an RCD. I don't see how anyone can argue that it doesn't apply to SELV.
Furthermore is there not still a requirement to bond all the CPCs?
 16 April 2009 09:15 PM
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GeoffBlackwell

Posts: 3846
Joined: 18 January 2003

It does apply to SELV circuits but that was not intended and will be changed.

Regards

Geoff Blackwell
IET » Wiring and the regulations » selv in a commercial wetroom

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