Q&A for How to Install Outdoor Electric Wiring

Make sure to secure the conduit within 3 feet of where it connects to the box. Then, every 10 ft (3.04 m) after that, secure the conduit within 3 ft (0.91 m) of every coupling.

If it's outdoors, you can use EMT tubing with "rain-tight" fittings - do not use set-screw (concrete tight) fittings. If it's underground, then you should use PVC. There are also waterproof flexible metal conduits with vinyl/PVC cover that are the best for wet areas.

NM cable (aka "Romex") could probably be used without any issue, but UF cable can go anywhere NM can -- and more. The safer bet is to use UF, or ask your inspector what he'd like to see in this situation.

You may run the cable underground or overhead, as described in the article above.

Not all outdoor wiring requires a conduit. However, conduit may offer some advantages, as mentioned in the article above. Many regulations permit direct burial of a suitable cable in a proper trench without conduit, or using an overhead cable.

No. Wiring in conduit MUST be supported or buried. The conduit may be any approved method - but the easiest for most people is Schedule 40 PVC. Mount the conduit to the fence with clips / straps made for the type of conduit you're installing every 5 feet (and 1 foot from the pipe's ends) at a convenient height or dig a trench for the pipes below the frost line.

Find a convenient location inside the house for taking the wires from an existing circuit through the outside wall, whether it's in the attic, basement or at the top or bottom of an existing interior wall. Drill a hole for the cable and attach an exterior-rated junction box on the outside end of hole. Either attach your lighting to that box or run conduit or UF cable to another exterior-rated box at the desired location. Add a switch to the circuit inside the house to control the outside floodlights.

According to the US National Electrical Code, all types of overhead cables need to be at least 8 feet above the ground and 3 feet in all directions at the edges. It is better to use weather-resistant cables if they are going to be outside.

A good option is PVC insulation, because it is durable and can withstand heat and moisture. Another option is rubber insulation, which is also tough and can handle different environmental factors. You have to choose a cable with the right gauge size so that it can handle the power required by your lawn mower.