Gazebo wiring - outdoor requirements

Question

I am planning to install a kit gazebo in the back yard. I plan to install a 15 or 20 amp GFCI breaker in the panel and run 14/2 or 12/2 (as appropriate) UF cable to the gazebo buried at a minimum depth of 12". I will put the cable in conduit on the exterior of the house to 12" below grade, and the cable will enter the gazebo through a 90 degree sweep placed prior to pouring the concrete slab into the hollow wooden gazebo leg. I am reasonably confident that this will meet NEC (and local) requirements for running cable from the house to the gazebo.

I plan to install an outdoor rated ceiling fan under the gazebo roof, and a lightswitch and an outlet mounted in weatherproof boxes to the gazebo legs facing the inside of the gazebo. Getting power from one of these locations to the others will require me to run cable through the hollow gazebo legs and along the roof rafters. This is where I'm unclear about requirements.

If I run the cable through the hollow leg of the gazebo to the roof rafters, and secure the cable to the top side of the rafters appropriately, would I require conduit? If not, how frequently must the cable be secured to the rafters and what fasteners are appropriate?

I believe this would be a NEC 'damp' location. Can the same UF cable used for the underground run also be used inside the gazebo legs and along the roof rafters? If not, what cable should I use?

Answer 1

I would seriously consider using conduit the entire distance. In particular, if you use rigid metal conduit then you can put it only 6" below the surface instead of 12". That makes for a much easier dig, and you are already dealing with conduit at the ends anyway. Why do this? Rodents. 12" + GFCI makes it human safe. But, in my area at least, you still have to worry about all kinds of creatures, many of whom like to dig holes underground. If you use rigid metal conduit then you have a better chance of a long-lasting installation than with UF cable.

Once you switch to conduit for the whole distance, you should use individual wires instead of cable. I would make sure the conduit is a little larger than absolutely necessary for an easier pull and so that you can add more wires/circuits later if needed or upsize if needed. I would recommend starting with 12 AWG and 20A, but with conduit if you start with 14 AWG and 15A you can upgrade without having to trench again.

As for inside the gazebo, yes that is a damp location so either wires in conduit or UF cable. Plus, as pretty much anywhere except inside walls, cables need to be protected from damage (conduit takes care of protecting wires). So I would stick with wires and conduit. But you could switch from industrial looking metal to PVC if you prefer the look. You can also cover up the conduit, as long as you don't block any junction boxes or conduit bodies as they need to remain accessible. If you can get conduit into the hollow gazebo legs then you won't see it at all except where it attaches to junction boxes, etc.