regs v manufacturer

OK this is in reference to outdoor in-ground lighting. Said lighting will be encased in concrete.

Some lighting I have been asked to fit specs Natural Rubber flex is to be used and are clearly not deisgned in any way to use SWA. Cables and lights will be encased in a concrete platform approx 450mm thick. So I can't get to recommendation of 600mm regardless!

Now with regards to depth, regs actually say 'at a suffucient depth to avoid being damaged by any reasonably forseeable disturbance of the ground'  as this is a walk way around a listed building I would have 200/300 mm of concrete is proabably deep enough? It's not the sort of place anyone bar an Approved Contractor is ever likley to be working.

Now regs also say buried cable   'except where installed in a conduit or duct which provides equivalent protection against mechanical damage, a cable buried in the gorund shall incorporate an earthed armour, metal sheath or both....'  so this begs the question, if the manufacturer states natural rubber flex who wins regs or manufacturer?  Given that the duct is in solid concrete (no metal re-bar) could a normal plastic copex be used - don't fancy trying to terminate armoured copex to the light fittings as this would effectively mean I have to modify fittings.

I've always thought that most of the stuff about SWA, depth of cables really refers to cables across soft ground, where it makes perfect sense, but to me cables in solid concrete is somewhat different? Can't think of anything being more protective than 6" of concrete, apart from 7" of concrete  :^O

Your opinions please.

A couple of weeks back I was fault finding some garden lighting ................ out of 8 lights fitted 3 years ago, 5 had extremely low IR - this was down to the cable - HN05 (supplied with the lights) .

The manufacturer seemed to think that as long as the units had lasted 1 year, the cables were suitable.

So install with flex at your peril .............

as for 600 mm - that is irrelevant in concrete IMHO

Murdoch said:

A couple of weeks back I was fault finding some garden lighting ................ out of 8 lights fitted 3 years ago, 5 had extremely low IR - this was down to the cable - HN05 (supplied with the lights) .

The manufacturer seemed to think that as long as the units had lasted 1 year, the cables were suitable.

So install with flex at your peril .............

as for 600 mm - that is irrelevant in concrete IMHO

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Knightsbridge or Saxby by any chance?

Philips 

cable is Ho7RN-F 

H07RN-F also known as EPR / PCP flexible mains and control cable is designed primarily as a trailing cable for use in the supply of energy for portable or mobile equipment. The cable can also be used in drainage, water treatment, cold environments and severe industrial environments and can withstand weather, oil/grease, mechanical and thermal stresses.

Murdoch said:

as for 600 mm - that is irrelevant in concrete IMHO

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Tis what I am thinking, but justifying it against interpretation of regs by the likes on the NICEIC is another matter, not that they have any guidlines for the above.

binky said:

Tis what I am thinking, but justifying it against interpretation of regs by the likes on the NICEIC is another matter, not that they have any guidlines for the above.

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AFAIR the 600mm refers to areas on farms

There is no guidance in BS 7671

the reg is quoted above - it's an opinion thing.... :^O

kerching said:

Knightsbridge 

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Hit , nail and head.

There response regarding the matter was under whelming to say the least - in fact they weren't even that bothered.....

So Knightsbridge - no more 230v spike lights for me or my customers..............

has to be said, if you run lights in 12V you can basically throw cables across the ground...

Murdoch said:

So Knightsbridge - no more 230v spike lights for me or my customers..............

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****esbridge....

A firm I worked for used them for everything, cheap and not so cheerful! 

Many many recalls...I bet they haven't learned though!

Ho7RN-F  was my preferred outdoor cable where SWA wasn't required, wired my whole shed with it though that's only 12v...

Still haven't got over my phobia of FP and I've got two floors of an office block to wire in FP 200 gold! 

:facepalm:

Blue Duck said:

****esbridge....

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Funny

I've installed many outdoor lighting systems ........ often supplying the cable myself and never had a problem.

I think they are using sub standard, imported carp for their cables .......

Knightsbridge: the mark of quality (is missing)!

I would suggest that the cable being buried in concrete will protect it effectively from mechanical damage as there is no ground to disturb (if you just label the concrete as "Caution, cable conduit do not move or damage" )

Using plastic ducting in the concrete should be fine as long as it is cable duct as it is then designed to provide protection against mechanical damage.

I would agree that where thee is a solid layer of material over the cable then it is only necessary to provide limited protection thereafter, but probably a good diagram of where the cables run might be useful at a later date.

If you were to install a cable and cover it with concrete cable covers this would be the same effect.

H07RNF is meant to be the cable of choice for outside use after SWA and NYY-J.

Who remembers the original FP that you had to use plastic ferrules with?......apart from greater than 5 cores when the MIs said "wrap a bit of tape around it"

just recalling

Just found in the outer spiral arm of Shed number 96 ......

not me and they defo dont look fireproof

The Ali screening in the cable was so sharp,that these had to be fitted to stop the insulation being damaged. Each drum came with a bag of ferrules shoved inside it

Looks like a Golden Virginia tobacco tin to me, got a couple in my tool bag with a cable round them, one with Allan keys in it and one with an emergency selection of crimps.

roys said:

Looks like a Golden Virginia tobacco tin to me, got a couple in my tool bag with a cable round them, one with Allan keys in it and one with an emergency selection of crimps.

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Pretty certain it's an Old Holborn tin, as that what was what I used to smoke when I thought it was Big and Grown Up and Cool

You could always use this stuff

It comes with its own draw string already installed.