ELECTRICAL CONDUIT QUESTION:
I am a general remodeler who occasionally must do small electrical projects in the course of my jobs. I am on one now (small commercial building) that requires some exterior lighting installed on the flat roof structure and parapet wall. I intend to use standard 1/2″ electrical conduit (ridgid) and #12 strand wire (White, black & Green). Is this standard for an EXTERIOR APPLICATION? Or do I need some more weather protection (different kind of fittings or something?) Also should I use this wire or is there a variety intended for outside use (such as UF is intended for underground rather than standard Romex)??? MANY THANKS!
Replies
wa2 - No offense intended but your post tells me that what you need is a good electrical contractor. What you are doing is illegal in most places I've ever worked in, particularly for commercial work.
T. Jeffery Clarke
OK, Jeff... Thank you for your post, but please educate me... What is required? PVC conduit? etc...
Without knowing the details I can't proscribe a solution. For informational purposes and admitting that this is MHO I offer the following:
Unless there is reason to believe that the location of the conduit is subject to abuse, I would go with EMT and compression fittings. The boxes should be weatherproof with threaded hubs, fastened through exterior tabs and hubs sealed with pipe joint compound.
PVC conduit, not plumbing pipe, might also serve. It is more sensitive to physical abuse and may, given a few years, degrade in sunlight, despite being sunlight resistant, but it can be painted with latex paint and may be preferred over EMT where there are concerns about corrosion. Chlorine from pool equipment and ammonia from manure piles can eat EMT or RMC in a matter of months, especially at the joints, even when painted or coated.
Single conductors, THHN or THWN, with properly colored coded insulation and with a ground wire would be my choice. A conduit ground, with metallic conduit, would be legal in most cases but I prefer the redundancy of the dedicated ground wire bonded to each box and connected to all devices. Being an exterior circuit it may be required to be protected by GFI.
Be careful and seriously consider hiring a professional. Compared to the cost of a visit by an ambulance or fire department using an electrical contractor is cheap insurance. Check the local codes. Most jurisdictions follow the NEC but there can be considerable variation in detail and local preferences.
Thanks 4LORN1! Appreciate the very helpful suggestions!!!!!