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Topic Title: Fire alarm supply cable colour
Topic Summary: is red acceptable????
Created On: 24 November 2009 06:30 PM
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 24 November 2009 06:30 PM
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nlasen

Posts: 164
Joined: 23 December 2006

Hi all, when wiring the feed to a fire alarm panel our firm usually uses red FP200 , but on the current job the main contractors are telling us that the supply should never be red incase someone cuts through it thinking its a fire alarm cable at 24v not 230V . Is there any ruling saying this is against the regs or rerasons why it should not e in red?

Oppinions appreciated.

Nick
 24 November 2009 06:53 PM
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sutton1020

Posts: 135
Joined: 29 January 2008

nick don't think any good spark would cut through a cable because its 24volts as this can cause damage also ,but i think its good practise to wire the 230v in white cable ,jim
 24 November 2009 07:26 PM
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intrinsic4225B

Posts: 1623
Joined: 30 September 2004

The Electricity at Work Regulations 1989 have no lower limit of voltage to which they apply - so people shouldn't be going round randomly cutting any cables, regardless of the sheath colour or the voltage expected to be present.
 24 November 2009 07:45 PM
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intrinsic4225B

Posts: 1623
Joined: 30 September 2004

As an aside, BS1710:1984 Specification for identification of pipelines and services specifies the colour orange as the identification identification colour for electrical services.
 24 November 2009 09:03 PM
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broadgage

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Joined: 07 August 2007

This has been disscussed before, though I cant find the thread.
My view is that regulations require that fire alarm wiring be in a distinctive colour, which in practice means red.
My view is that the 230 volt supply is a part of the fire alarm system and therefore should be red.

Others however took a different view and stated that only the ELV parts should in red, with white, orange or some other colour being used for the mains supply.
 26 November 2009 01:43 PM
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OMS

Posts: 19593
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I tend to concurr with Broadgage

From the definitions in BS 5829.Part1:2002 and AMD2:2008

circuit
assembly of fire alarm components supplied from the same control equipment and protected against overcurrent by the same protective device(s) or current limitation arrangements


And from Section 2:

25.2 Recommendations for mains power supplies
The following recommendations are applicable to the low voltage mains supply to the system.

NOTE 1 This supply should be regarded as an integral part of the fire alarm system, particularly for the purpose of certification
of the system (see Clause 41), regardless of whether the electrical installation within the building is provided by the organization
responsible for installation of the fire alarm system.


And from Clause 26.2

o)
....................
All fire alarm cables should be of a single, common colour that is not used for cables of general electrical services in the building, to enable these cables to be distinguished from those of other circuits.
NOTE 13 The colour red is preferred.


So:

1 - the mains supply to the fire alarm forms part of the system

2 - The mains supply cable is a fire alarm circuit

3 - It should be the same colour as the fire alarm system - the prefered colour is red

4 - The main contractor is an idiot - particularly if he believes cable identification by sheath colour forms tha basis of a safe system of work

Regards

OMS

-------------------------
Failure is always an option
 26 November 2009 03:22 PM
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eclipse

Posts: 142
Joined: 03 November 2006

Have to agree with the comments OMS has posted, we would never put in a supply to a fire alarm panel in anything else but a red sheathed cable, be it MICC or FP 200

-------------------------
Thanks

Alan.

Now what was that reg no?
 26 November 2009 09:22 PM
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sparxxxx

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Bit of fawning going on here, as usual.

The supply to a fire alarm panel is no different to a supply to anything else it should be the same colour as other supply cables. And definitely never red or white, someone suggested it should be orange.

To that someone read the regs.
 26 November 2009 10:34 PM
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intrinsic4225B

Posts: 1623
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Originally posted by: sparxxxx

The supply to a fire alarm panel is no different to a supply to anything else it should be the same colour as other supply cables.


How can this be the case when BS7671 references BS5839 in 110.1 (xxv) and BS5839 contains Clauses 25.2 and 26.2?

And definitely never red or white, someone suggested it should be orange.


Why never red or white? Where is this prohibition regarding cable sheath colours specified in BS7671 or elsewhere?

If white a white sheathed cable should never be used for an low voltage (LV) circuit, then what of all the installated low smoke and fume (LSF) twin and earth cable, which has a white sheath?

My earlier post did not state the the LV supply to a fire alarm panel should be wired in an orange sheathed cable, simply that BS1710 specifies orange as the identification colour for electrical services - this could be applied to a cable, a containment system or an underground duct.
 26 November 2009 10:42 PM
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paulskyrme

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IF you refer to BS EN 60204-1, (the equivalent to BS7671 for machinery) Orange is the colour generally accepted to be for singles which are live with the general machine supply isolator OFF.
Such as panel lighting that may be required to be ON with the machine turned off for repair and maintenance reasons.

Paul

Edited: 26 November 2009 at 10:59 PM by paulskyrme
 27 November 2009 12:11 AM
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micjamesq

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In order to facilitate identification of fire alarm circuits, cables should preferably be red in colour, unless another form of colour coding is appropriate. By this means, the possible need for appropriate segregation can be identified, and there will be less likelihood of inadvertent manual interference with the circuits of fire alarm systems (e.g. during work on other electrical circuits).

Include me in the fawning group

Yes OMS that's fawning not f(aw)nicating - I have re-deployed my Pascal triangle back into my pocket

Regards

-------------------------
E & OE
 27 November 2009 10:23 AM
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OMS

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Originally posted by: sparxxxx

Bit of fawning going on here, as usual.

The supply to a fire alarm panel is no different to a supply to anything else it should be the same colour as other supply cables. And definitely never red or white, someone suggested it should be orange.

To that someone read the regs.


The supply to a fire alarm system is clearly different to the supply to anything else - it is clearly identified in BS 5839.Part 1 as being an integral part of the fire alarm system (see definition of circuit in my post above).

In essence it is simply a 230V fire alarm circuit and as such is usually both fire rated and coloured accordingly ie preferrably red in colour. As such it needs to comply with both BS 7671:2008 in terms of electrical safety and BS 5839.Part1 2002 and A2:2008 in terms of fire safety.

It might be worth you having a read through BS 5839.Part1 to enlighten you

OMS

-------------------------
Failure is always an option
 27 November 2009 12:59 PM
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slittle

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We always treat it as part of the system and therefore it's red FP200 from the DB to the fire alarm.

However I've always thought that if the fire has reached the point of destroying the supply cable to the alarm system then the fire alarm/detection system has sort of missed the boat hasn't it ??.


Stu
 27 November 2009 01:12 PM
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intrinsic4225B

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Originally posted by: slittle

However I've always thought that if the fire has reached the point of destroying the supply cable to the alarm system then the fire alarm/detection system has sort of missed the boat hasn't it ??


I suppose its all down to where the fire starts - I do recall reading a case study once where a fire disabled the fire alarm system of a building before the alarm was given, which I think lead to some fatalities.

That said, I think the case study in question was quite some time ago and the system involved was a simple manual system, presumably without any form of battery back up.

I'll have a look when I get home and see if I can find the details on it.
 27 November 2009 03:00 PM
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OMS

Posts: 19593
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Originally posted by: slittle

We always treat it as part of the system and therefore it's red FP200 from the DB to the fire alarm.

However I've always thought that if the fire has reached the point of destroying the supply cable to the alarm system then the fire alarm/detection system has sort of missed the boat hasn't it ??.

Stu


But the presumption here would be that the fire that destroyed the supply cable also caused operation of the detection devices (or was spotted and the alarm raised via BGU's) and that full or phased evacuation is in progress.

Essentially, the mains cable needs to be fire rated because it would be expected to supply both the detection and alarm load in teh event of battery (or other standby supply ) failure.

Regards

OMS

-------------------------
Failure is always an option
 27 November 2009 03:03 PM
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OMS

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Originally posted by: intrinsic4225B

Originally posted by: slittle

However I've always thought that if the fire has reached the point of destroying the supply cable to the alarm system then the fire alarm/detection system has sort of missed the boat hasn't it ??


I suppose its all down to where the fire starts - I do recall reading a case study once where a fire disabled the fire alarm system of a building before the alarm was given, which I think lead to some fatalities.

That said, I think the case study in question was quite some time ago and the system involved was a simple manual system, presumably without any form of battery back up.

I'll have a look when I get home and see if I can find the details on it.


Although careful siting of teh CIE should tend to avoid that problem.

From Clause 23.2.1 -

e) The fire alarm control and indicating equipment, ELV power supply equipment for the control and indicating equipment and other essential control facilities should be sited in areas of low fire hazard
level, so that the equipment is unlikely to be involved in a fire before adequate warning has been given.


Regards

OMS

-------------------------
Failure is always an option
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