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Topic Title: Requirement to glue every conduit joint?
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Created On: 01 November 2017 07:13 PM
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 01 November 2017 07:13 PM
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TimJWatts

Posts: 421
Joined: 07 August 2013

Hi,

There's no requirement to glue every joint in a conduit system is there?

(Containing single insulated cable, indoors dry environment).

I have an inspection swept bend that would be easier to keep removable but there are conduit saddles within 2" of both ends.

With the clips in place it seems to be impossible to remove.

One branch goes into a screw male adaptor screwed into a Wiska box, so I have to be able to spin this to remove. Also, it would be tricky to get everything lined up in the 3 seconds it seems to take the solvent weld to set!


Thank you

Tim
 01 November 2017 07:26 PM
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Alcomax

Posts: 245
Joined: 12 November 2009

As long as any bits cannot pop out, no problem. In fact best to always allow for expansion with PVC tube.
 01 November 2017 07:33 PM
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TimJWatts

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Cool - Thank you very much
 01 November 2017 08:01 PM
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sparkingchip

Posts: 10100
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Why are you using conduit and where?

Andy B
 01 November 2017 08:11 PM
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Fm

Posts: 1733
Joined: 24 August 2011

Put conduit in place, place pencil mark across adaptors/ pipe.
Dismantle apply glue line up pencil mark
Repeat


Vaseline for the other side of an expansion coupling
 01 November 2017 10:24 PM
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TimJWatts

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Heating control
 01 November 2017 10:25 PM
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TimJWatts

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Oh - and in my house - dry environment.
 02 November 2017 09:39 AM
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Zoomup

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I normally glue plastic conduit if it is to be installed outside. And I make drain holes in fittings at the lowest points to allow draining of water/condensation. Also as others have said, expansion joints are necessary to avoid snaking of the conduit when temperatures rise, especially if the conduit is likely to be soaked in sunshine. I use synthetic grease in expansion joints to allow free movement. Even indoors I glue plastic conduit to ensure that it will not easily come apart, say when children play with it, or it gets knocked. It is not just a Lego kit after all and should be a permanent safe installation method.

Z.
 02 November 2017 10:32 AM
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TimJWatts

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Hi,

Thanks for the reply.

This is the joint in question

All my other joints are glued, except this and one end of a slip coupling to allow a bit of movement (but that will be boxed in).

OK - this joint: it's a very tight fit and geometrically, it's impossible to pull off without unclipping saddles on both legs.

I really wanted to use a BESA box here, but discovered I didn't have a "right angle" one - that would have been a good solution as it would be screwed down.


The reason I didn't glue this particular joint was partly that the other end needs to screw into a Wiska box (box is threaded, there's no ring nut) so you need to be able to unplug and spin the tube to get it seated correctly and partly I was afraid of a bad glue job and ending up with it slightly at the wrong angle which would risk having to remake a quite a bit.


Given all that, should I maybe replace it with a BESA or attempt to glue it? Would be a bit of a pain as I'd have to pull the wires back out.

To be honest, if the metric is "cannot come apart in the hands of a child" - it won't. In fact it would be easier to snap the screw adaptor on the WISKA box - I know, because I did that taking it apart last night to glue the joint up top! Had to recut a bit of tube, thankfully a straight
 02 November 2017 10:46 AM
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mapj1

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It will be just fine. It meets IP4X and cannot be opened without a tool, no need to gold plate the requirements.

I have known folk put a self tapping screw sideways into the joints, in other cases where falling off actually was a problem, but I think while that may work on guttering, it introduces a risk of stabbing the wire, that is best avoided.
If you really really want to, just drill and rawlplug into the wall though the back of the elbow, but you certainly don't need to.

Actually as an aside, even with the lid off it would still meet IPXXD as the 35mm dia ball will not go in, and a 1mm diameter 100mm long wire will not reach far enough towards the ends of the wires to become live.



edited for clarity.

-------------------------
regards Mike


Edited: 03 November 2017 at 01:31 PM by mapj1
 02 November 2017 10:58 AM
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AJJewsbury

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I wouldn't glue conduit joints for indoor dry environments - just use enough & correctly placed saddles to make sure it can't be pulled out accidentally. (BTW probably metal saddles these days to comply with the don't collapse in case of fire requirement).

You'll regret gluing them when it comes to future alterations....

- Andy.
 02 November 2017 11:12 AM
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TimJWatts

Posts: 421
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Thank you Mike and Andy. I used glue where I thought a joint could pop easily and on all threaded adaptors. So that started me wondering whether the requirement was absolutely to glue, or merely (and more common sense), "that it doesn't fall apart easily".

It's good to understand these things better - when (if) I ever build my workshop, I'll be using full conduit and singles there.

BTW - am I right that bends don't have gaskets available - BESA boxes do. I was curious, as this means you'd have to use BESA everywhere outside, or silicone the lids on plain bends (I have seen that done).

Cheers!

Tim
 02 November 2017 12:48 PM
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dustydazzler

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I personally only glue plastic conduits when installation outside or likely to be pulled on inside
 02 November 2017 12:55 PM
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AJJewsbury

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BTW - am I right that bends don't have gaskets available

I think that many avoid 'inspection' bends - preferring just to bend the conduit itself (PVC conduit is easy to bend with nothing more than a bending spring) - so unless space is really right, the problem doesn't arise.
- Andy.
 02 November 2017 11:00 PM
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sparkingchip

Posts: 10100
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Fixing plastic tube with a clip both sides of a elbow is potentially bad practice as it restricts movement due to expansion and contraction with temperature change.

Perhaps not too much of an issue with electrical conduit, but definitely not correct for the installation of plastic waste pipe.

Solvent welding the fittings and less clips may be considered good practice.

Andy B.
 03 November 2017 08:21 AM
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Zoomup

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Having now had a look at the photo of your job, it looks very neat and tidy and done in a good workmanlike manner. I do not think that you need to worry about gluing the joint in question. A good friction fit is o.k.

Bye,

Z.
 03 November 2017 08:28 AM
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Zoomup

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Manufacturer's examples of expansion and contraction. The problem is mainly seen with long lengths of plastic conduit and large temperature changes. http://www.primeconduit.com/Te...nsion_Contraction.pdf

Z.
 03 November 2017 09:10 AM
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RJB83

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Originally posted by: mapj1


Actually as an aside, even with the lid off it still meeds IP4x as the 35mm dia ball will not go in, and a 1mm diameter 100mm long wire will not reach far enough towards the ends of the wires to become live.




Hi Mike, firstly I am sure you are correct but....would you mind explaining the following...

I've had a look and I cannot understand where the 35mm diameter ball comes from?

Also it was my understanding that the trunking had to be IP4X regardless of access to live parts? Thats how I'm reading 521.10.1?

-------------------------
Regards,

Rich
 03 November 2017 09:33 AM
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AJJewsbury

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Also it was my understanding that the trunking had to be IP4X regardless of access to live parts? Thats how I'm reading 521.10.1?

IP4X or IPXXD - the 35mm sphere comes from the standard test for IPXXD (which basically tests for access to live parts (using a 100mmx1mm probe attached to a 35mm diameter ball) rather than checking the size of holes in the outer enclosure).
- Andy.
 03 November 2017 12:36 PM
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RJB83

Posts: 81
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Andy, I've actually just found a previous thread that you and Mike were involved in which explains it nicely. I understand now!

http://www.theiet.org/forums/f...d=205&threadid=104323

Thanks for the response

-------------------------
Regards,

Rich
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