PVC conduit nail clips

[Peter Greer]

Hi

Im new to this forum so thanks for having me. Ive been sparking for many years but work alone mostly so don’t get much of a chance to ask fellow sparks their opinion on things. A lot of my work is agricultural and my question relates to surface mounted PVC conduit. I use cable nail clips when fixing long runs of conduit to wooden roof beams for lighting circuits instead of spacer bar saddles. I find it much faster but my question is Are these nail clips an acceptable method to surface mount PVC conduit as they are designed for cable, not conduit? 
thanks

 

[Sharpend]

Welcome Peter, 

I think you’ll find that the 18th edition will require some form of metal fixing, we always put up a couple of metal saddles on a length. 

 

[Andy™]

as above, it needs to be supported against falling in a fire. plastic clips alone do not comply. you can get black & white metal saddles

 

[Risteard]

You can get round clips for conduit. Typically only use them in a track (chase) which is being plastered over. 

 

[Evans Electric]

As said above ,   add a  few metallic  clips  .   I  don't see a problem with using the giant cable type  clips  just to hold PVC conduit  . All I can think of is saddles are designed to let the conduit expand & contract through them .       There is a high  linear expansion with PVC conduit , hence the need for lots of saddles . 

Run it horizontally in direct sunlight  and you'll see the droopy result after a good summer. .  

If you've had no problems carry on . 

 

[kerching]

You can get round clips for conduit. Typically only use them in a track (chase) which is being plastered over. 

Crampets...I think

 

[Risteard]

Crampets...I think

Not crampets - these are PVC clips for conduit. Crampets are steel and need to be drilled and plugged to fix. These just have nails in them.

 

[Peter Greer]

Thanks for your replies, I would only use pvc conduit inside and mostly at high level in large farm buildings for lighting circuits so there would be no effect from sunlight really. Yes I’m aware that they do not meet the fire requirement but what would your views on using the plastic nail clips as described in conjunction with a metal saddle at regular intervals along the run. The appeal of the nail clips is the speed at which they can be installed into wooden roof beams so if the fire regulation could be met without having to screw each fixing in would be desirable

 

[Evans Electric]

Yes , as the others said ,  just fit the occasional metallic  clip or strap  .    A bit of perforated band say ,  or just the odd metal 20mm saddle  will cover that Reg.  

The whole point of the Reg is to prevent cable / conduit fixing  melting in a fire  and hanging down , entangling escapees &  firemen . 

 

[Peter Greer]

Thanks Evans electric and others. I was trying to insert a picture of the clip I’m referring to but am unable to. I find the 22-26 size cable nail clip fits perfectly over 20mm pvc conduit. So would it be considered an acceptable method for surface mounting pvc conduit or perhaps would have been before 18th edition fire regs came in?
 

 

[Sharpend]

Is the conduit fixed -Yes, 

does it comply with 17th - yes

is it considered best practice? Probably not

if used in conjunction with metal saddles for 18th compliance then don’t see a problem. As you say it’s up high in a farm building can’t imagine farmer being to fussy as to appearance. 
on a wall or low level it may look piggin**** but each to their own? 

 

[Peter Greer]

Hi sharpend

I have to say that it looks quite neat actually when completed. Incidentally others are commenting on the conduit expanding in sunlight. The only conduit that I ever use is white. Would I be right in saying that black conduit would expand more than white?

 

[Risteard]

Use expansion couplers to deal with expansion.

 

[Sharpend]

Black loves a bit of sunshine to show off its length. 

 

[SPECIAL LOCATION]

This thread reminded me of some PVC conduit I saw running along a walkway by a carpark entrance to our local Tesco's...

The walkway gets a fair amount of direct sunlight.....

Interesting choice of saddle size.....

Not to mention saddle spacing?

:|

 

[kerching]

Next door neighbour has a very badly installed solar system

black 25mm plastic conduit down outside south facing wall

we can judge the temp by looking out of kitchen window to,see how distorted the conduit is

 

[Sharpend]

This thread reminded me of some PVC conduit I saw running along a walkway by a carpark entrance to our local Tesco's...

The walkway gets a fair amount of direct sunlight.....

Interesting choice of saddle size.....

Not to mention saddle spacing?

:|

View attachment 10823View attachment 10824View attachment 10825

Perhaps they’d been advised about expansion joints and thought they needed expansion saddles :C  by the looks took neither piece of advice. 

 

[Peter Greer]

I think I’ve only installed black pvc conduit a couple of times ever. White pvc conduit is standard where I’m from. It looks like they have taken the max spacing distance from the regs literally. I would normally have a support every couple of feet when conduit is horizontal. Presumably white conduit wouldn’t expand as much as black would? 

 

[Andy™]

I think I’ve only installed black pvc conduit a couple of times ever. White pvc conduit is standard where I’m from. It looks like they have taken the max spacing distance from the regs literally. I would normally have a support every couple of feet when conduit is horizontal. Presumably white conduit wouldn’t expand as much as black would? 

i use black often - usually try and keep to the same colour as the downpipes / gutter etc, whatever will blend in best. often its black. for spacings, rather than measure everything i usually go every 2 bricks horizonal & 5 or 6 bricks vertical

 

[Evans Electric]

I think I’ve only installed black pvc conduit a couple of times ever. White pvc conduit is standard where I’m from.

This seems to be a location thing with some stuff.    I use very little white conduit .  

Darn sarf  apparently  they only use white Twin/earth   where I'd have to order it in if I wanted white,   twin /E is always grey here.