Advice for underground cables

[Jon-uk]

I need someone to point me in the right direction for the right equipment to allow electrical cables (low and domestic voltage) to exit neatly from underground runs.

Maximum cable bunches will be 3-4 and it seems overkill using a man hole and chamber, but no matter how much I search I cannot find smaller equivalents that will allow me to neatly exit the cables rather than just have the ducting exit the soil.

Thanks.

 

[Iggifer]

What size and what type of duct is installed?

 

[Jon-uk]

There will be two 2" and 4" round pipe.

 

[Iggifer]

They do duct access pits/covers but they're still 300x300mm and solid lids

I suppose it depends what's happening with the cables once they leave the duct as to the best plan of attack.

No point putting a solid lid on anything if you're bringing the cables out through the same place.

 

[Jon-uk]

OK thanks, I was hoping that there would be something smaller!

 

[winston1]

I need someone to point me in the right direction for the right equipment to allow electrical cables (low and domestic voltage)

Meaningless. By domestic voltage I assume you mean 240 volts, but that IS low voltage.

 

[Jon-uk]

Correct, then both low voltage.

 

[winston1]

So he needs to tell us what the voltages are.

 

[Jon-uk]

240v AC, plus 12 and 24 v DC

 

[Jadele]

I need someone to point me in the right direction for the right equipment to allow electrical cables (low and domestic voltage) to exit neatly from underground runs.

Maximum cable bunches will be 3-4 and it seems overkill using a man hole and chamber, but no matter how much I search I cannot find smaller equivalents that will allow me to neatly exit the cables rather than just have the ducting exit the soil.

Thanks.

Can you tell us more about the application. Why the duct size is what it is. What its supplying. How its to be used. I appreciate that it can be of little relevance but when skinning a cat?

 

[Jon-uk]

Sure, it is 2” flexible pipe running underground beneath soil and gravel. It will carry 240 volt AC, and 12/24 v DC cables and exists at ground level.

Will supply a water feature and a outside shed.

 

[Jadele]

OK well I would bring it out of the ground up a wall or wooden post that you put in to the bottom of an IP rated box attached to said wall or post. You could then if you wanted do some local switching on the box and send the individual cables back out using stuffing glands to the various devices. One point is that technically you shouldn't mix cables of ELV and LV or band 1 and 2. Its one of them though that it will probably never be an issue and is done all the time but it is technically not meant to be done. Picture is kind of what I am thinking. Also you need to make sure that the duct is deep or use a solid duct which also should really be deep so as not to get damaged by a spade etc. A flexi duct will provide no real protection which is where the lack of separation of your band 1 and 2 cables could be an issue. All the power out to these items should be RCD protected and if I was you I would have it either on its own breaker or on a double pole isolator in the house so you can disconnect the external wiring if a fault happens that ends up tripping the house power off.

 

[ban-all-sheds]

One point is that technically you shouldn't mix cables of ELV and LV or band 1 and 2.

"Technically"?

I do hope by that that you don't mean the OP should regard that regulation as a minor frill, of little practical merit.

Its one of them though that it will probably never be an issue and is done all the time but it is technically not meant to be done.

Done all the time by those who don't think that fires and death are not "issues".

 

[ban-all-sheds]

I need someone to point me in the right direction for the right equipment to allow electrical cables (low and domestic voltage) to exit neatly from underground runs.

Doesn't your electrician know?

 

[Jon-uk]

Thanks Jadele, really useful reply.