690.31 B doesn't mention anything about mixing ac and dc PV system conductors in the same raceway/wire way. 690.4 B still allows you to do so.
Separation for AC and DC wires in a wireway
In regards to NEC690.31(B), I'm no longer permitted to share a wireway among AC and DC wires in a wireway, as I used to be able to do. Unless I separate them by a partition.
For most groups of string inverters, it is geometrically inconvenient to construct a raceway for each, given that the AC and DC knockouts are both on the bottom surface. I'd end up with a spaghetti bowl of conduit, instead of a spaghetti bowl of wire in a common raceway.
How rigid is this rule? Is it so rigid, that not one single inch of AC and DC wires are permitted to be in proximity without a partition? Or will it be acceptable as long as I follow it for the majority of wire length?
What counts as a partition for the separating? Must it be metallic? I'd like to use PVC wire duct, with those slotted fingers, and adhere it to the wireway interior.
Obviously, at each inverter along the length, wires have to enter and exit. This would make a couple inches of nearby AC and DC wiring which could violate the rule. In order to get around this, I'd probably use split loom tubing.
For most groups of string inverters, it is geometrically inconvenient to construct a raceway for each, given that the AC and DC knockouts are both on the bottom surface. I'd end up with a spaghetti bowl of conduit, instead of a spaghetti bowl of wire in a common raceway.
How rigid is this rule? Is it so rigid, that not one single inch of AC and DC wires are permitted to be in proximity without a partition? Or will it be acceptable as long as I follow it for the majority of wire length?
What counts as a partition for the separating? Must it be metallic? I'd like to use PVC wire duct, with those slotted fingers, and adhere it to the wireway interior.
Obviously, at each inverter along the length, wires have to enter and exit. This would make a couple inches of nearby AC and DC wiring which could violate the rule. In order to get around this, I'd probably use split loom tubing.
1 - 3 of 3 Posts
We trry to keep ac/dc wiring seperate as much as we can. I have put metal dividers in the duct which becomes nasty when the duct gets full and after 10 years it always seems to be full. It does make it hard for condiut layout. I have seen some guys run the ac or dc inside a piece of sealtite that lays in the duct, usuallly the group of wires that are the smallest. A lot of our machines have very limited AC, mostly motors, so they run the motor leads in a sealtite and the dc wiring lays in the duct. Pretty sure this is a violation of the code but it works out for us. Just trying to keep the AC noise away from the DC inputs and outputs.
1 - 3 of 3 Posts
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