Seal underground cable duct

irishchris

Have pv cable running in 50mm cable ducting rising 2ft s above ground. What would be the best way of sealing this from water ingress and rodents?

2011

Water ingress in underground ducting isn’t normally a concern.
Is there a particular problem in the area with rodents?
I wouldn’t normally seal underground ducting.

Maybe you can provide more detail.

Malcomex

I'd probably just make up a steel cap and seal it on

I think rodents can also chew through the ducting if they're so inclined but I wouldn't expect that to happen

Outside at poles all I ever see is a silicone seal

Risteard81

You can get duct sealant. It's not cheap. More useful to keep out noxious gases etc., or even to prevent rodent infestation.

meercat

You can get ducting caps. You may have to notch it though

https://www.draindepot.co.uk/50mm-duct-pipe-end-cap.html

irishchris

2011 wrote: »

Water ingress in underground ducting isn’t normally a concern.
Is there a particular problem in the area with rodents?
I wouldn’t normally seal underground ducting.

Maybe you can provide more detail.

When I say underground, it rises two feet on either side. One side under pv panels and other side in outside of house wall. Using it for high voltage pv cables over a 25 run. There is not a big problem with rodents but next door neighbour has chickens and attracts some rodents with the chicken feed which then have made their way into my property.
I would have assumed water intgressing with cables inside the pvc duct over long term would be an issue?
Is it possible to use cement mix to seal?

irishchris

Risteard81 wrote: »

You can get duct sealant. It's not cheap. More useful to keep out noxious gases etc., or even to prevent rodent infestation.

I have seen these online but struggling to find Irish retailer with them?

2011

Risteard81 wrote: »

You can get duct sealant. It's not cheap. More useful to keep out noxious gases etc., or even to prevent rodent infestation.

For noxious gases I have used transit blocks alright in pharmaceutical plants as well as oil and gas applications. Normally we would specify Roxtec.

meercat

irishchris wrote: »

I have seen these online but struggling to find Irish retailer with them?

https://www.screwfix.ie/p/floplast-sp296-socket-plug-black/46863?gclid=EAIaIQobChMIkLftpK267gIV0WDmCh2BTATkEAQYAiABEgLOYPD_BwE&gclsrc=aw.ds

I’d say most plumbing supplies/hardware would have something similar

irishchris

meercat wrote: »

https://www.screwfix.ie/p/floplast-sp296-socket-plug-black/46863?gclid=EAIaIQobChMIkLftpK267gIV0WDmCh2BTATkEAQYAiABEgLOYPD_BwE&gclsrc=aw.ds

I’d say most plumbing supplies/hardware would have something similar

Cheers looking for something which allows two 4mm cables through though and as rodent/water proof as possible

Malcomex

irishchris wrote: »

Cheers looking for something which allows two 4mm cables through though and as rodent/water proof as possible

You could do something like sealant down the pipe

Pack with wire wool

Waterproof top with more sealant

Wire wool is commonly used on holes in outside walls as rodents won't chew through it.

meercat

irishchris wrote: »

Cheers looking for something which allows two 4mm cables through though and as rodent/water proof as possible

https://www.amazon.co.uk/Hooded-Extractor-Grille-Draught-Shutter/dp/B00GOU2I1Y

https://www.electricalworld.com/en/ie/Zexum-M20-IP68-Nylon-Cable-Gland-with-Locknut---Grey/s-2576-5784.aspx?PartnerID=73&utm_source=google&utm_medium=shopping&utm_campaign=Ireland&gclid=EAIaIQobChMIjbjT8LW67gIVV-3tCh3j1wu9EAQYAiABEgLow_D_BwE

irishchris

meercat wrote: »

https://www.amazon.co.uk/Hooded-Extractor-Grille-Draught-Shutter/dp/B00GOU2I1Y

https://www.electricalworld.com/en/ie/Zexum-M20-IP68-Nylon-Cable-Gland-with-Locknut---Grey/s-2576-5784.aspx?PartnerID=73&utm_source=google&utm_medium=shopping&utm_campaign=Ireland&gclid=EAIaIQobChMIjbjT8LW67gIVV-3tCh3j1wu9EAQYAiABEgLow_D_BwE

??
Maybe I haven't explained right sorry. This is for a single 50mm duct external and not going into house

meercat

irishchris wrote: »

??
Maybe I haven't explained right sorry. This is for a single 50mm duct external and not going into house

Can you gland cables into the blank cap that I linked earlier and use the grille cover to protect from moisture ingress

Malcomex

meercat wrote: »

Can you gland cables into the blank cap that I linked earlier and use the grille cover to protect from moisture ingress

Hardly worth the bother compared to sealing the top of duct?

He said rodents so they can chew through most except metal if it's a concern

2011

I have to ask, why the concern about water ingress?
Even if the ends are sealed really well the ducting may not be sealed all the way along it’s length. Typically joins in underground ducting are not watertight. It would be best to ensure that the cabling within the duct then water ingress shouldn’t be an issue.

irishchris

2011 wrote: »

I have to ask, why the concern about water ingress?
Even if the ends are sealed really well the ducting may not be sealed all the way along it’s length. Typically joins in underground ducting are not watertight. It would be best to ensure that the cabling within the duct then water ingress shouldn’t be an issue.

I'd of assumed over time water would degrade the outer sheath of cables. I'm using 4mm double insulated pv cable. Perhaps it's not an issue then just assumed maybe it would have been?

2011

irishchris wrote: »

I'd of assumed over time water would degrade the outer sheath of cables. I'm using 4mm double insulated pv cable. Perhaps it's not an issue then just assumed maybe it would have been?

You could check with the cable manufacturer do see if this is an issue. If it is I would suggest using a different cable type, if thy is not an option then you will have the difficult task of installing ducting that is completely waterproof throughout its length including every join. Even then there may be an issue with condensation so some sort of drainage would be required.

Most cabling installed in underground ducting does not suffer from these issues.