Cable trays in domestic installation

[slartybartfast]

Having house rewired, and thinking of making use of 600mm wide horizontal galvanised cable tray secured between joists in ceiling. Can the cables simply be layed in the tray or do the regs. require that each cable is secured to the tray & what sort of fixings are allowed?

 

[plugsandsparks]

Not each cable, but if you are using a tray that wide, then you can run your data cables, alarm cables and the like on one side and power cables on the other. Some fixings should be used to keep them apart and make it look elegant even professionally done.
Basket can also be used and keeps cable temps down, but for a house i would hope that is not an issue

 

[Pete999]

Having house rewired, and thinking of making use of 600mm wide horizontal galvanised cable tray secured between joists in ceiling. Can the cables simply be layed in the tray or do the regs. require that each cable is secured to the tray & what sort of fixings are allowed?

Hardly a cost effective exercise imo.

 

[slartybartfast]

Hardly a cost effective exercise imo.

How can you say that when you know nothing of the rationale behind it? Its dirt cheap and noise on the overall rewiring cost and the convenience in this case outweighs the cost.

 

[Pete999]

How can you say that when you know nothing of the rationale behind it? Its dirt cheap and noise on the overall rewiring cost and the convenience in this case outweighs the cost.

Just think of the problem when trying to install cable tray in a rewire, and for your information, I have probably rewired more properties than you have had hot dinners, 600mm cabletray between joist my foot.
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How can you say that when you know nothing of the rationale behind it? Its dirt cheap and noise on the overall rewiring cost and the convenience in this case outweighs the cost.

Out of interest, what rationale are we thinking about?

 

[Andy78]

I don't understand the idea behind this at all, but I do know it will significantly increase time, costs, and disruption to the rewire.

I can't think of any regulations that would require cables to be fastened to the tray in this instance, but if you're going to all that effort you might as well secure them every 100mm with metal tie wraps just to on the safe side.

 

[slartybartfast]

Just think of the problem when trying to install cable tray in a rewire, and for your information, I have probably rewired more properties than you have had hot dinners, 600mm cabletray between joist my foot.
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Out of interest, what rationale are we thinking about?

Its part of the core cabling for the house and will likely need to run additional cables in future. This run joins consumer unit at one end with main riser to floors 2, 3 & loft at other end. The cable tray will run parallel with joists, and beneath will be a sections of ceiling that are designed to be easily removed. Will make things super convenient and helps with future proofing.

BTW - As its a rewire am kitting the CU out 100% with RCBOs. Again a no brainer for convenience - as in the event of any fault I will only lose one circuit. The incremental cost of RCBOs is lost in overall cost.

 

[pc1966]

...if you're going to all that effort you might as well secure them every 100mm with metal tie wraps just to on the safe side.

If the tray is horizontal as I think the OP is proposing it would not need metal ties as the cables could not drop in a fire.

 

[Andy78]

If the tray is horizontal as I think the OP is proposing it would not need metal ties as the cables could not drop in a fire.

Yes I know, but as the idea was to use unnecessary methods I thought I'd stick with the plan.

 

[telectrix]

2 ft. wide tray in a house? that's more overkill than Roger Rabbit.

 

[7029 dave]

IMO regarding the fixing of the tray worries me, in the event of a fire wood burns, the fixing will be to that wood (CORRECT) , a lot of weight there with cables attached.!!

 

[pc1966]

IMO regarding the fixing of the tray worries me, in the event of a fire wood burns, the fixing will be to that wood (CORRECT) , a lot of weight there with cables attached.!!

To be fair, by time your beams have burned through is long past the point where "fire escape" make sense.

 

[telectrix]

and at least he can recover the tray for scrap value.

 

[7029 dave]

To be fair, by time your beams have burned through is long past the point where "fire escape" make sense.

What about the emergency services its a hazard.

 

[pc1966]

Next point to debate: Earth the tray or not?
I'm throwing my hat in the earth bonding corner, but I also quite like yellow/green wire.

 

[Andy78]

Next point to debate: Earth the tray or not?
I'm throwing my hat in the earth bonding corner, but I also quite like yellow/green wire.

Use the tray as main bonding conductor. It just needs painting green and yellow its entire length ?

 

[davesparks]

Its part of the core cabling for the house and will likely need to run additional cables in future. This run joins consumer unit at one end with main riser to floors 2, 3 & loft at other end. The cable tray will run parallel with joists, and beneath will be a sections of ceiling that are designed to be easily removed. Will make things super convenient and helps with future proofing.

600mm tray will completely fill the gap between joists, if it fits at all.
So access from ceiling panels would require the tray to be installed upside down and so fixings would be required for all cables.

Without knowing the size of the house or the size of the installation required it is very hard to comment on this plan.

Have you had quotes from electrical contractors yet? Or had anyone look at it yet with a view to quoting the job?
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IMO regarding the fixing of the tray worries me, in the event of a fire wood burns, the fixing will be to that wood (CORRECT) , a lot of weight there with cables attached.!!

By the time the joists have burned enough for the tray to drop the house will be gutted, anyone inside long dead and burned to a crisp and the fire brigade certainly won't be going inside.

 

[pc1966]

So access from ceiling panels would require the tray to be installed upside down and so fixings would be required for all cables.

My take was a false ceiling, so the tray might be hung down from the joists using M10 stud or whatever in the usual "lips up" style to allow cables to be laid on top. But hopefully the OP can clarify this.

 

[ipf]

2 ft. wide tray in a house? that's more overkill than Roger Rabbit.

Why? 2ft tray's ideal for breakfast in bed..

 

[telectrix]

customer: "i want all my underfloor cables on 600mm tray. what steps will you takee
electrician: "bloody great big ones back to the van".