Plastic conduit

[Maxxy]

Hi all. Just installed some plastic 20mm conduit in an underground carpark. Its all tight, and well held, around 1.5m per run, with a couple of inspection bends.

The question im wondering, is whether it needs to be glued to comply with the regs? Does anyone know where in the regs ill find it? Or is it just good practice to glue it, or only if it needs the ip rating?

Cheers

 

[Taylortwocities]

I always glue it. It expands and contracts with heat/cold. You'll get extremes of both in a carpark as well as those little erks who like to test things with their feet.

If you dont glue it you'll find its all come apart in 6 months.

 

[ColJack]

best not to glue it in long straight runs unless it is exposed to water..

also a good idea to not push the ends in all the way..

this allows for expansion in warmer weather and stops the conduit kinking or bowing..

 

[Lectrician]

If you are worried about expansion - fit EXPANSION COUPLERS! These are designed to allow slip. Glue all joints if you so wish, and grease the slip expansion couplers.

Look at the manufacturers charts for spacings of expansion couplers. It is around every 5m for straight runs of 20mm.

On huge long runs, it is best not to fix any of the circular boxes either - leave them to move.

Basically, glue if you want. The only reason I generally dont is to allow for easy alterations. If you are ever concerned about expansion - use the CORRECT fitting, and you will be fine.

Out of interest, did you run around the wall and tee up into the fittings, or tube 'through' the fittings? Tubing through is not a great idea unless you fit an expansion coupler between each light as the tube is bound swan around and meander after a year or two.

The manufacturers (MT MITA ETC) produce, and wholesalers sell, glue, sealing grease and expansion couplers - not rocket science

 

[Maxxy]

Nah its literally 1.5 metres long at the most, running out of metal boxes, down to carbon monoxide detectors. So theres no long runs etc, expansion/contraction wont occur over the length of it, and theres 2 or 3 supports on each of them. It was just a case of whether the regs say the joints need to be glued

 

[Lectrician]

I just noticed "underground" - I wouldn't bother gluing at all.

No need for expansion couplers either by the sound of it.

 

[Maxxy]

cool. the extra info will come in handy in the future! Its all up out of the way for this job, otherwise i would have use metal conduit for the extra protection