SWA in drain permissable?

[dksanders]

Hi All,

I've been asked to get a supply for a car park PIR light across the car park entrance from the existing light. The only way across would be by running the SWA cable in a drain that runs across the driveway (see picture).

Is there any reason that I shouldn't do that? I can't think of any regulation of the top of my head that prohibits it.

TIA

 

[Yozza19]

Fit the yellow and black sleeping policemen with the cable runs inside rated at 30 tons some of them if screwed down correctly there is your ansew

 

[davesparks]

Hum ......... this has come up on here so many times - a simple table of recommendations would resolve about 95% of questions

A table of recommendations would cause more trouble than good. Just look at how a simple note that a reading above 200ohms may not be stable has resulted in the majority of electricians misunderstanding this as being the value they should aim for.

 

[davesparks]

SWA is waterproof, however it is not intended for continuous submersion in water.

I remember reading an article about this which concluded that there are better cables than PVC sheathed SWA for use under water.

The major issue is that the slightest bit of damage to the sheath will allow water to get in and rot the armour.

 

[davesparks]

A table of recommendations would cause more trouble than good. Just look at how a simple note that a reading above 200ohms may not be stable has resulted in the majority of electricians misunderstanding this as being the value they should aim for.

What’s funny?
Another example is the model forms and example lists of items which may need inspection as part of an EIC or EICR. These are recommendations in an appendix which are almost universally treated as what must be done, and people keep complaining about being required to fill in these endless tick sheets.

Any suggestions or recommendations in the regulations get treated as a reason to avoid any sort of independent thinking or application of a technical knowledge of thought process.

 

[dksanders]

digging a narrow trench in the tarmac, about 1ft. inside from the drain, 12" to 15" deep, would not be too difficult, and a better solution all round. IMO.

Agreed, but the cost wouldn't be accepted by the committee. They've had to spend a lot recently getting bringing things up to standard and there's not a lot of budget left.

 

[dksanders]

Fit the yellow and black sleeping policemen with the cable runs inside rated at 30 tons some of them if screwed down correctly there is your ansew

I've never used them before but they look like the solution thanks. They'll add an additional £200 to the bill though so may not get accepted. Great suggestion, thanks.

 

[LankyWill]

Agreed, but the cost wouldn't be accepted by the committee. They've had to spend a lot recently getting bringing things up to standard and there's not a lot of budget left.

A rogue from the pub with a disc cutter could cut that tarmac out and fill it with tarmac in a bag for £80 you tight arse.

 

[Dave OCD]

Solar light ?

 

[bigspark17]

You need a proper duct a minimum of 450mm below surface with warning tape above it. Then run SWA through this duct. If budgets would not stand two poles and a catenary then I can not see that budget will stand a proper duct. Tell customer price for doing a proper job with a duct line dedicated to electrical cable. If he will not pay the price for a proper job then walk away.

Where does it say in regs it must be buried 450mm & in a duct???

Fit the yellow and black sleeping policemen with the cable runs inside rated at 30 tons some of them if screwed down correctly there is your ansew

That would be expensive than digging up the road!


Common sense says the swa will be more than safe in that soakaway, use 30mA for additional protection.

 

[dksanders]

Solar light ?

I don't think one would give light for enough hours especially in the winter.

 

[Lucien Nunes]

Running any cable in a drainage channel is a daft idea. They need de-silting from time to time and that is likely to be done with a drop scraper with a metal blade. By the time that happens, the cable will be submerged in silt and will go unnoticed, so the blade will be dragged along the channel gouging through the sheath of the SWA. By the time the guy with the scraper notices, the cable will be as waterproof as a tea bag and he'll go nuts. "Could've b****y killed me, live cable hidden in there like that!" Even if the cable is indestructible, it'll stop the channel being scraped clean, would have to go down on hands and knees with a trowel and work round it. Mutual detrimental influence: Cable obstructs maintenance of channel, channel puts cable at risk of damage.

The ramp sounds like a possibility.

 

[Octopus]

I've never used them before but they look like the solution thanks. They'll add an additional £200 to the bill though so may not get accepted. Great suggestion, thanks.

You are best off giving them a price to do it properly.... If they choose to go else where with a cheaper price and a less than suitable solution then that's their lookout.

 

[dksanders]

Running any cable in a drainage channel is a daft idea. They need de-silting from time to time and that is likely to be done with a drop scraper with a metal blade. By the time that happens, the cable will be submerged in silt and will go unnoticed, so the blade will be dragged along the channel gouging through the sheath of the SWA. By the time the guy with the scraper notices, the cable will be as waterproof as a tea bag and he'll go nuts. "Could've b****y killed me, live cable hidden in there like that!" Even if the cable is indestructible, it'll stop the channel being scraped clean, would have to go down on hands and knees with a trowel and work round it. Mutual detrimental influence: Cable obstructs maintenance of channel, channel puts cable at risk of damage.

The ramp sounds like a possibility.

Have you seen my photos, the drain is 3" wide and 2" deep.

 

[bigspark17]

Running any cable in a drainage channel is a daft idea. They need de-silting from time to time and that is likely to be done with a drop scraper with a metal blade. By the time that happens, the cable will be submerged in silt and will go unnoticed, so the blade will be dragged along the channel gouging through the sheath of the SWA. By the time the guy with the scraper notices, the cable will be as waterproof as a tea bag and he'll go nuts. "Could've b****y killed me, live cable hidden in there like that!" Even if the cable is indestructible, it'll stop the channel being scraped clean, would have to go down on hands and knees with a trowel and work round it. Mutual detrimental influence: Cable obstructs maintenance of channel, channel puts cable at risk of damage.

The ramp sounds like a possibility.

Yes as all drains get desilted regularly lol

 

[DPG]

I think other members have covered it pretty well already. Not a good idea at all. I certainly wouldn't put my name to it.