External Power Advice....

[JohnW2]

I'm sure there is a reg somewhere about cables having to be suitable for the environment where they are used. Would you bury BS8436 cable directly in the ground and then claim that you had exercised reasonable skill and care etc?

There probably is such a regulation. However, as I said, I presume that those who wrote 522.8.10 must have believed that there are some non-armoured cables which have an earthed screen and which are suitable for direct burial, otherwise they would presumably not have mentioned it as an acceptable option for directly buried cables (not in conduit or ducts).

Kind Regards, John

 

[JohnW2]

.... as I said, I presume that those who wrote 522.8.10 must have believed that there are some non-armoured cables which have an earthed screen and which are suitable for direct burial, otherwise they would presumably not have mentioned it as an acceptable option for directly buried cables (not in conduit or ducts).

As a P.S., it seems that at least some types of pyro (which offer very limited mechanical protection) are said by the manufacturers to be suitable for burial - e.g. this one which says:

... The Pyro MI cable shall also be available with an overall LSF covering. This may be employed to protect the copper sheath from corrosive environments, to provide identification by colour, or for other aesthetic reasons. When cables are to be buried in the ground, the type having this outer covering should be specified.

... and ...

The Pyro MI cable system must be capable of the following installation types: -
Buried in the ground
Underground ducts, conduit or pipes
Buried in concrete
Buried in plaster
Surface mounted
On cable tray
Outdoor and wet conditions ......

Kind Regards, John

 

[ban-all-sheds]

I'm not sure what that document is - in places it reads like a set of requirements one might issue to a contractor, "The Pyro MI cable system must be capable of ....".

But I am unconvinced that a maker's decree can override mechanical properties, laws of physics etc, and I disagree that directly buried MICC offers adequate protection against impact.

Also, note that even if you do agree, you have to take account of the performance of the entire system, insulation and all, not just the copper tube.

 

[EFLImpudence]

What is adequate protection against impact?

SWA doesn't offer much protection against impact.
It is merely hoped that ADS will be achieved; the same as MICC.

 

[ban-all-sheds]

The requirement is for it to resist damage, not to deal with damage via ADS.

 

[JohnW2]

But I am unconvinced that a maker's decree can override mechanical properties, laws of physics etc, and I disagree that directly buried MICC offers adequate protection against impact.

So what non-armoured cable with a earthed metal sheath do you think 522.8.10 is saying can be directly buried (not in conduit or ducting)?

Kind Regards, John

 

[JohnW2]

SWA doesn't offer much protection against impact. It is merely hoped that ADS will be achieved; the same as MICC.

Quite. Mechanical protection and facilitation of ADS are alternatives - buried underground is really no different from buried in walls in that respect - pyro or ali-tube cable (not that I have ever met any!") in walls do not have to provide (or be provided with) mechanical protection as well as facilitating ADS.

That's why I think that 522.8.10 is worded badly if, as BAS has interpreted it, it means that underground conduit/ducting is acceptable (to protect a cable that would not, itself, be suitable for direct burying) if it provides 'equivalent' mechanical protection to that provided by a cable with an earthed sheath (with or without armour) - since the 'cable with an earth sheath' is providing protection by ADS, not by mechanical protection.

Kind Regards, John

 

[ban-all-sheds]

So what non-armoured cable with a earthed metal sheath do you think 522.8.10 is saying can be directly buried (not in conduit or ducting)?

TBH, I don't know. I've never stopped to wonder and then investigate.

 

[JohnW2]

TBH, I don't know. I've never stopped to wonder and then investigate.

One of the problems seem to be that, even when a manufacturer says that a non-armoured cable is suitable for direct burying, you feel that it is not suitable, presumably because you do not regard it as having adequate mechanical protection.

Do you have the same view in terms of cables buried in walls (i.e. would not regard pyro or ali-tube acceptable because of the inadequate mechanical protection)? If not, why do you see a difference between these two different versions of 'burying'??

Kind Regards, John

 

[Crossed Wires]

 

[Crossed Wires]

Yes:

​

It will not be armoured cable.

​

So you know where you stand regarding what the regulations say about burying your cable, but you still plan to do it.

That does not seem like the behaviour of someone who cares.



Burying the cable in PVC conduit.

Wow, I wish I had your crystal ball. So you've seen the appliance that I'm using and the cable connected to it, impressive.

I do care but imagine if no one anywhere was allowed to bury a cable....wow, good work dude. You'll then complain of trip hazards.

I don't believe I mentioned PVC in regards to conduit, something you must be guilty of yourself. I think you'll find that regs say the cable should be buried around 450 - 600mm and marked with warning tape at around 150 down. Besides, as it's going in some of this... https://www.screwfix.com/p/adaptaflex-liquid-resistant-covered-steel-conduit-25mm-x-10m-black/42878 I'm sure we'll sleep well in the knowledge that it's not bare cable laid directly under the patio.

Anyway, back to my point about the RCD etc I think I'll just stick one of these on the wall...
https://www.electricaleurope.com/en...-IP66-Weatherproof-Outdoor-Socket/m-1833.aspx

 

[Crossed Wires]

So you know where you stand regarding what the regulations say about burying your cable, but you still plan to do it.

Err this bit. If you follow the regs then you're safe to bury it. You make it sound like it's a forbidden job.

Show us the conduit you planned to use.

Err....look at my previous post

They don't actually specify a depth. But they do specify that the cable should have integral mechanical protection or be provided with it externally.

Not entirely true but hey.

Inadequate.

Wow, thanks. Why?