pyro cable in council flats

[beatrixtiff]

Hello there, been asked to take a look at an old council flat as the owner wants to put some surface mounted cables in mini Trunking or conduit.

When I arrived to take a look, I discovered that the cables visible on the walls are wired in pyro.....

Is this legal these days for this type of situation or does it have to be changed? The property is in London.

Any advice or help appreciated, thanks.

Rob

 

[m4tty]

I can't really help you but would have thought pyro is the best cable which will far outlast any other

 

[Doc Hudson]

There is nothing illegal about using Pyro, or any other type of cable for that matter. Providing the cable (whatever type) is of a sufficient grade to carry any expected loads, is correctly protected and is electrically sound. Ins Res, Earth continuity etc. Pyro may well be the best choice for certain external influences and/or cheaper than say metal conduit.

Doc H.

 

[Technician]

Pyro cheaper than conduit...that is interesting. I would have thought it to be the other way around. Looking at Reg 422.6 it is the correct choice where the installation is in locations of national significance. Just hope the tests prove it is OK.

 

[lkayelectrical]

Nothing wrong with pyro I guess it will put last all our life times if it has been made of correctly

 

[Andy™]

Hello there, been asked to take a look at an old council flat as the owner wants to put some surface mounted cables in mini Trunking or conduit. When I arrived to take a look, I discovered that the cables visible on the walls are wired in pyro.....

Is this legal these days for this type of situation or does it have to be changed? The property is in London.

Any advice or help appreciated, thanks.

Rob

pyro will probably outlast any other cable if the ends are made correctly. why do you think its 'illegal'?

 

[Evans Electric]

The "legality" of using pyro is not an issue Beatrix , and although I refer to them often , there are no Electric Police in this country...............yet!!

 

[Doc Hudson]

Pyro cheaper than conduit...that is interesting. I would have thought it to be the other way around. Looking at Reg 422.6 it is the correct choice where the installation is in locations of national significance. Just hope the tests prove it is OK.

Quite so, Technician I think I meant to put 'have been' rather then 'to be the best choice'. I was considering the OP's description of it being an old installation, unknown how old or the size or extent of the Pyro run, bends and obstacles to go around or through, but prior to the recent hike in copper prices looking at the total costs of materials and labour to install the run it may well have been more cost effective to run pyro. But then again it may well have just been aesthetics?

Doc H.

 

[Technician]

I take the points about the price of copper and the prospective life of the installation.

During my sea going days on some of the older vessels I noticed that the boiler room electrics

were in "Pyrotenax" because of the higher temperatures.

It was well known that these systems began to fail within the first ten years of the vessel life. It may have been simply a matter of the termination quality.

Replacement had to be in Butyl or similar because it was considered that the cost of renewal in the original was prohibitively expensive.

I was told (by some) that the vibration caused the Magnesium oxide to compact and settle causing the conductors to contact each other or the sheath. I now wonder if it is more likely that the vibration work hardened the sheath material causing it to crack.

Newer tonnage did not use so much of it, and its use was confined to shorter lengths around the boiler burner platforms.

 

[Sidewinder]

Technician,

I suspect that you may well be correct in that the failure of the Pyro may well have been due to the vibration issues, as it does not like vibration for all of the reasons that you have posted really.

There are many building wiring materials that are susceptible to movement damage, i.e. vibration.

The filler could have compacted, the inner or outer cores may have fatigued, there could have been poor terminations, all exaggerated by the vibration perhaps.

An excellent wiring material though in the correct application don't you think?

Regards,

By the way, you can edit your posts at the bottom right hand corner near the PM, Reply, Reply With Quote buttons you will see an edit button, if you click this you can edit your post to correct your typo's and spelling etc. as sometimes it is hard not to make an error when typing into this software I find.

HTH

 

[Technician]

Sidewinder; it is a superb wiring system. I go to Salt's Mill in Saltaire and a lot of Pyro (MI) is still there. Some people in the past were in the habit of polishing it, an activity that DOES lead to work hardening.

It is all very well, subject it to PIV (Propellor Induced Vibration) which becomes a massive problem on larger vessels with large unsupported steel divisions that vibrate with alarming consequences and......look out.