Conduit Drains for RMC

J

jbolen

Senior Member
I have a large project with exposed RMC that enter N3R enclosures with approved hubs the local Electrical inspector say I have to install drains on all conduits per Art 314.15.
 
dkidd said:
ARTICLE 314
Outlet, Device, Pull, and Junction Boxes;
Conduit Bodies; Fittings; and Handhole
Enclosures
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I don't see one of those items mentioned in the OP. As Strathead stated drains are not required if the conduits are installed in such a way that water cannot accumulate or the 3R equipment already has integral drain slots or holes.
 
From my experience, from a practical prospective, no matter how well you seal this up things water gets into the outdoor RMC installation. We had to go back and install drains on an emission station for a power plant that was sealed properly when installed. Water had infiltrated over a period of a few years affecting the condition of the installation. If you are piping up a job with the expense of RMC it will probably be there for a while, water, over time has a way of getting in. The code may not require drains as stated above, but the NEC requirements can be bettered.
 
Also with RMC the couplings are not watertight so even if water accumulate within a horizontal run of the raceway it would drain out through the couplings.
 
jbolen said:
I have a large project with exposed RMC that enter N3R enclosures with approved hubs the local Electrical inspector say I have to install drains on all conduits per Art 314.15.
Click to expand...
314.15 Damp or Wet Locations “ In damp or wet locations, boxes, conduit bodies, outlet box hood, and fittings shall be placed or equipped so as to prevent moisture from entering or accumulating within the box, conduit body, or fitting. Boxes, conduit bodies, outlet box hoods, and fittings installed in wet locations shall be listed for use in wet locations. Approved drainage openings not smaller than 3mm (1/8 in) and not larger than 6mm (1/4 in) in diameter shall be permitted to be installed in the field in boxes or conduit bodies listed for damp or wet locations. For installation of listed drain fittings, larger openings are permitted to be installed in the field in accordance with the manufacture’s instructions.” 2023 NEC

While the NEC does not say “drainage shall be installed” in does recognize that water is likely to enter and is giving you a way to prevent a build up.
If you are going to the expense of installing RMC, and want to provide a lasting installation I don’t know way you are contesting drainage.
 
I will drill weep holes in boxes or conduit bodies if necessary. 3R cabinets will already have drain holes in them. What you really need to pay attention to is to avoid having raceway sections that have a low spot and can not drain. If you are in a location that does get below freezing temperature, such raceways with water trapped in them will split open when the water inside freezes. I guess it does drain after that happens though:oops:
 
kwired said:
I will drill weep holes in boxes or conduit bodies if necessary. 3R cabinets will already have drain holes in them. What you really need to pay attention to is to avoid having raceway sections that have a low spot and can not drain. If you are in a location that does get below freezing temperature, such raceways with water trapped in them will split open when the water inside freezes. I guess it does drain after that happens though:oops:
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We traced a control circuit fault for a couple weeks before we located a short section of conduit in a U shape. It had filled up with water, split, and pushed a couple of wires out the split that was on the top of the conduit. When the ice melted the split closed and caused a ground fault, but when it was frozen there was no ground fault.

We also stopped drilling holes in conduit bodies and started just cutting notches in the cover gasket.
 
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