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Posted By Topic: TPS under ground not in Conduit.

Feb 13 2018 11:17

I've always been careful to run normal TPS in conduit when running it underground. However while working with a new company I have been criticised for doing this. I've been told it is not needed and that just danger tape is necessary ( and obviously buried 500 mm down. I don't have a copy of the regs handy. Can someone shed some light on this for me. I don't totally trust my employers word.


Feb 13 2018 12:07

Direct buried TPS also requires the use of sand or soft stone free soil for 50 mm around the cable and then some form of mechanical protection.(cat B system)
3000 clause refers

The over all cost of conduit only (needs to be heavy duty conduit

It will caome down to the cost of HD conduit v's the use of send + mech protection. HD conduit on it's own may be the cheapest!

Feb 13 2018 12:21

Standard TPS cable can not be buried direct in the ground without additional protection and warning tape doesn't meet that requirement.
You need to use a category "B" wiring system which provides additional mechanical protection ( see section of 3000 for more details ).
You are not supposed to bury TPS in standard conduit either, ( but I suspect most people do )it can only be buried without further addtional protection if "Heavy Duty" Conduit is used.
Lately heavy duty conduit has become more available as it is required for some Solar installations , but most of the conduit the wholesalers have in stock is normally medium duty.


Feb 13 2018 12:42

Thankyou for your help. Just as I thought. I'm expected to take short cuts for this particular employer often. He does not like being Challenged on regulations. So not sure what to do really.


Feb 13 2018 13:34

Suggest you politely suggest he reads the section on Category B systems and explain the way that you read it is that your not permitted to bury it direct and that you won't do it that way if your the one signing off the COC

Feb 13 2018 17:43

I'll have a chat with 'em

Feb 13 2018 22:13


Feb 14 2018 09:27

You’re the one with your name on the CoC, and the one EWRB will come after if it goes pear shaped, so if the boss is a cheap arse, and doesn’t like being challenged on the regs, go work for someone else. It’s your career on the line, not his.