18th edition question

[Spoon]

I have been informed that a plasterboard ceiling is not considered to provide support for cables in the event of a fire, and that all wiring throughout its length will require support with (for example) steel straps, unless it is drawn through joist holes

The plasterboard comment is interesting... Who informed you of this?

 

[Spoon]

There’s not many instances where a new build would be effected by this other than if trunking is used to house the cables to the DB or any detached garages with surface conduit drops for accessories inside.

Plastic trunking is not the issue here as it will melt in the fire. The idea is to stop entanglement of firefighters with the copper cables within the trunking.

 

[Deleted member 9648]

The plasterboard comment is interesting... Who informed you of this?

Currently doing the 18th and this came from the tutor when we dissected the implication of the regulation. Got an NIC visit next month so will run it by him as well. But knowing how the IET interpret things it would not surprise me that plasterboard alone as a support would not meet the requirements

 

[netblindpaul]

Plasterboard has a 30 minute fire rating from building regulations.
Check the Electrcial Safety First website to see if the questions of plastic plugs has been addressed in the faq section.

 

[Deleted member 9648]

Plasterboard has a 30 minute fire rating from building regulations.
Check the Electrcial Safety First website to see if the questions of plastic plugs has been addressed in the faq section.

The fire rating of plasterboard was raised during the discussion, but this was not considered to meet the requirement for supporting wiring systems

 

[Octopus]

If this is so important, why is the reg in the BBB lacking vital information ?

And no I’m not suggesting anybody ignores it .... just that inspections on completed properties will make this almost impossible to verify ....

 

[Silly Sausage]

Are you suggesting you will ignore this regulation?


521.10.202
Wiring systems shall be supported such that they will not be liable to premature collapse in the event of a fire.
This is a blanket requirement, no distinction is given to areas of wiring or type of installation. I have been informed that a plasterboard ceiling is not considered to provide support for cables in the event of a fire, and that all wiring throughout its length will require support with (for example) steel straps, unless it is drawn through joist holes.
This will have implications for rewires where cables are often fished through areas where floors are difficult or impractical to lift for access.

Does that now over-rule a previous/current reg that cables could be laid, horizontally, unsupported in an inaccessible void?

 

[Deleted member 9648]

Does that now over-rule a previous/current reg that cables could be laid, horizontally, unsupported in an inaccessible void?

If such cables were 'liable to premature collapse in the event of a fire'...then yes it would.

 

[Deleted member 9648]

If this is so important, why is the reg in the BBB lacking vital information ?

How much vital information do you want? The regulation is very clear as far as I can see. Wiring systems must be installed to stay put and not collapse in the event of a fire. That clearly means they must be supported by fire resistant fixings to the structure of the building

 

[Silly Sausage]

If such cables were 'liable to premature collapse in the event of a fire'...then yes it would.

Would that apply to singles in PVC conduit laid between joists?

 

[Deleted member 9648]

Would that apply to singles in PVC conduit laid between joists?

Yes, the conduit would need to be secured with steel saddles to the side of the joist

 

[Octopus]

The fire rating of plasterboard was raised during the discussion, but this was not considered to meet the requirement for supporting wiring systems

What colour plasterboard was being discussed? Grey or pink ?

 

[Ian1981]

Are you suggesting you will ignore this regulation?


521.10.202
Wiring systems shall be supported such that they will not be liable to premature collapse in the event of a fire.
This is a blanket requirement, no distinction is given to areas of wiring or type of installation. I have been informed that a plasterboard ceiling is not considered to provide support for cables in the event of a fire, and that all wiring throughout its length will require support with (for example) steel straps, unless it is drawn through joist holes.
This will have implications for rewires where cables are often fished through areas where floors are difficult or impractical to lift for access.

Of course the plasterboard gives fire protection, upto 30 mins.
If it didn’t then we would have to regard the regulation regarding escape routes to domestic new builds currently to the 17th edition and provide metallic support above the plaster board ceiling in hallways and all the exits which is completely unnecessary.
Never been pulled off an Niceic assessment on this.

 

[Ian1981]

Plastic trunking is not the issue here as it will melt in the fire. The idea is to stop entanglement of firefighters with the copper cables within the trunking.

Hence my comment that the cables housed in the trunking will need metallic support against collapse

 

[Octopus]

How much vital information do you want? The regulation is very clear as far as I can see. Wiring systems must be installed to stay put and not collapse in the event of a fire. That clearly means they must be supported by fire resistant fixings to the structure of the building

with the greatest respect the BBB is vague in detail.....

If the IET considers plasterboard insufficient the BBB should clearly state this

As usual, a poorly written regulation open to interpretation .....

Being given 1 possible interpretation by a course tutor is complete tosh imho

 

[Silly Sausage]

Of course the plasterboard gives fire protection, upto 30 mins.
If it didn’t then we would have to regard the regulation regarding escape routes to domestic new builds currently to the 17th edition and provide metallic support above the plaster board ceiling in hallways to the exits which is completely unnecessary.
Never been pulled of an Niceic assessment on this.

I did some work in a Nursery stairwell years ago, and I was told to fit two layers of 12.5mm to provide at least 60 mins of fire protection.
I'm no structural engineer, but I'm not convinced about unsupported cables above a plasterboard ceiling require fire proof fixings. The property would be beyond saving by then.

When cables are visible, fair enough!

 

[Deleted member 9648]

Of course the plasterboard gives fire protection, upto 30 mins.
If it didn’t then we would have to regard the regulation regarding escape routes to domestic new builds currently to the 17th edition and provide metallic support above the plaster board ceiling in hallways to the exits which is completely unnecessary

Based on the information I have been given I think you are wrong, all of the guys on the course, including me took the same line s you regarding plasterboard, but the tutor insisted all wiring systems require support even if above a plasterboard ceiling. Plasterboard collapses during a fire, it may be the case that plastic water pipes will melt which will flood ceilings and cause collapse during a fire. The wiring above if not supported will collapse as well and not meet the requirements.

 

[Dave OCD]

How on earth would you fix cables running parallel between joists above a ceiling on a rewire or addition without major upheaval ?

 

[Octopus]

Based on the information I have been given I think you are wrong, all of the guys on the course, including me took the same line regarding plasterboard, but the tutor insisted all wiring systems require support even if above a plasterboard ceiling. Plasterboard collapses during a fire, it may be the case that plastic water pipes will melt which will flood ceilings and cause collapse during a fire. The wiring above if not supported will collapse as well and not meet the requirements.

Who is this “tutor” ? and who does he work for ? And why is he making seemingly unjustifiable statements about plasterboard?

 

[Ian1981]

Based on the information I have been given I think you are wrong, all of the guys on the course, including me took the same line regarding plasterboard, but the tutor insisted all wiring systems require support even if above a plasterboard ceiling. Plasterboard collapses during a fire, it may be the case that plastic water pipes will melt which will flood ceilings and cause collapse during a fire. The wiring above if not supported will collapse as well and not meet the requirements.

Funny but I think your tutor is wrong
By the time a plasterboard ceiling collapses then the house is pretty much done for
He must know more than most about the fire protection quality of plasterboard