Regarding cable entry into DC isolators via conduit, when isolator is indoors/adjacent PCE.
5033/2014 clause 4.4.4.6(c) states for DC isolators mounted outdoors, cable entry shall be on the lower face entry.
Amendment No. 2 (back of the book) clause 4.3.3.1, also states cable cable entry shall be the lower face entry, but doesn’t specify indoors or outdoors. So does this mean lower face entry for indoor DC isolators also?
I don’t fully understand the logic of top vs bottom entry here, water could still enter either way? Surely it’s more important to adequately seal the the other end of the conduit where exposed outside?
5033/2012 doesn’t seem to have such specific information regarding water ingress. I’m guessing working to this standard it would be acceptable to bog the conduit up with silicone and fit the conduit to the isolator enclosure anyway you see fit? The only rule you’d need to comply with is 3.3.2.3 of 3000?
Cable entry into DC isolator
Re: Cable entry into DC isolator
The is avoiding water ingress into the rooftop array output isolator or other equipment enclosures exposed to weather.
Yes 3.3.2.3 is relevant. Also 4.1.3.
Remember that while 2014 may be followed as guidance, the one we must comply with is the edition cited in Sched 2 of ESRs: 2012+A1+A2
But there's not much difference between them on this point (2012 clause 4.4.4.5 vs 2014 clause 4.4.4.6)
Both require the IP rating of the enclosure to be maintained .
Both require sealing.
Both recommend all entries via bottom, with 2014 giving more detailed info.
So certainly NOT "acceptable to bog the conduit up with silicone and fit the conduit to the isolator enclosure anyway you see fit".
The guidance WRT bottom entry is there, and clear, in the cited edition.
4.3.3.1 (both editions) also relates to the array and related equipment exposed to weather.
All these requirements are about preventing the water getting into enclosures.
There are no requirements aimed at preventing travel of moisture along the conduit (unlike for cool rooms).
I don't see that these requirements apply to an equipment enclosure that is located within the structure away from the weather
It's about maintaining the required IP rating,so where there's no required IP rating, then you can't compromise it.
Yes 3.3.2.3 is relevant. Also 4.1.3.
Remember that while 2014 may be followed as guidance, the one we must comply with is the edition cited in Sched 2 of ESRs: 2012+A1+A2
But there's not much difference between them on this point (2012 clause 4.4.4.5 vs 2014 clause 4.4.4.6)
Both require the IP rating of the enclosure to be maintained .
Both require sealing.
Both recommend all entries via bottom, with 2014 giving more detailed info.
So certainly NOT "acceptable to bog the conduit up with silicone and fit the conduit to the isolator enclosure anyway you see fit".
The guidance WRT bottom entry is there, and clear, in the cited edition.
4.3.3.1 (both editions) also relates to the array and related equipment exposed to weather.
All these requirements are about preventing the water getting into enclosures.
There are no requirements aimed at preventing travel of moisture along the conduit (unlike for cool rooms).
I don't see that these requirements apply to an equipment enclosure that is located within the structure away from the weather
It's about maintaining the required IP rating,so where there's no required IP rating, then you can't compromise it.
Re: Cable entry into DC isolator
Thanks Alec, appreciate the response. That’s what I was confused about, whether there is any requirements, as you say ‘aimed at preventing travel of moisture along the conduit’.
I’m guessing some common sense has to be employed here. Where a conduit system has a section in an outdoor environment, that connects to an indoor enclosure with an DC isolator, there’s a risk of moisture travelling into the isolator, so some preventative measures should be taken.
I’m guessing some common sense has to be employed here. Where a conduit system has a section in an outdoor environment, that connects to an indoor enclosure with an DC isolator, there’s a risk of moisture travelling into the isolator, so some preventative measures should be taken.
Re: Cable entry into DC isolator
I agree that if water enters an exterior enclosure, there's some risk of it travelling along the conduit (or within a cable) to an interior enclosure.
Especially if the exterior enclosure is higher.
However, throughout Wiring rules, this risk is generally dealt with by taking measures to prevent moisture entry into the exterior enclosure.
If it can't get in, it can't travel.
Sealing of the conduit to prevent moisture travel is not required (but also not specifically prohibited).
However it could also be counter-productive.
Exterior equipment enclosures are subject to ambient temperature variations, causing the air within to expand and contract.
In a fully-sealed enclosure, this can lead to moisture being sucked in through the seals.
A conduit provides a path for the enclosure to "breathe" .
The only case I know of where particular anti-moisture-travel measures are required is cool rooms [6.6.4.2 of "3000"].
This is not about external moisture entering, but rather the air within the conduit contains moisture which can condense in the colder environment.
Preventing exchange of air between the conduit in the room and the warmer section outside minimises the total amount of such condensation over time.
There are also special requirements for hazardous areas wiring (cables & wiring enclosures) leading between electrical fittings within zones and outside the Zones; to prevent travel of explosive gas mixtures along the wiring / enclosure.
If "5033" had wanted to deal with moisture travel, it would have been equally explicit as these special rules.
So in my view best to concentrate on ensuring IP rating of the exterior enclosures is not compromised
If you want to go further, entry at bottom of the interior enclosure will be the best option - but not specifically required.
Especially if the exterior enclosure is higher.
However, throughout Wiring rules, this risk is generally dealt with by taking measures to prevent moisture entry into the exterior enclosure.
If it can't get in, it can't travel.
Sealing of the conduit to prevent moisture travel is not required (but also not specifically prohibited).
However it could also be counter-productive.
Exterior equipment enclosures are subject to ambient temperature variations, causing the air within to expand and contract.
In a fully-sealed enclosure, this can lead to moisture being sucked in through the seals.
A conduit provides a path for the enclosure to "breathe" .
The only case I know of where particular anti-moisture-travel measures are required is cool rooms [6.6.4.2 of "3000"].
This is not about external moisture entering, but rather the air within the conduit contains moisture which can condense in the colder environment.
Preventing exchange of air between the conduit in the room and the warmer section outside minimises the total amount of such condensation over time.
There are also special requirements for hazardous areas wiring (cables & wiring enclosures) leading between electrical fittings within zones and outside the Zones; to prevent travel of explosive gas mixtures along the wiring / enclosure.
If "5033" had wanted to deal with moisture travel, it would have been equally explicit as these special rules.
So in my view best to concentrate on ensuring IP rating of the exterior enclosures is not compromised
If you want to go further, entry at bottom of the interior enclosure will be the best option - but not specifically required.
Re: Cable entry into DC isolator
They also make Anti condensation vent valves that can be fitted to exterior enclosures to help prevent condensation.
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