Spring is in the air, and with it comes spring cleaning and spring projects! Many of which require electricity. Perhaps you want to setup a woodshop in your shed, or put a power post in your yard to plug in that whipper snipper. Today we’ll discuss properly running electrical power to your shed, or to a power post in your yard using rigid conduit lines. So throw away that extension cord (that you’ve mowed over several times) – and let’s get digging!
The first step is planning. You have two options – using Underground Feeder (UF) cable, or a Rigid Metal Conduit (RMC). Today we’ll be focusing on RMC. Though slightly more expensive, RMC is a better option — and best of all, requires far less digging. A RMC shielded cable must be buried 6″ below the ground surface, whereas UF must be buried 12-18″ below the surface. Here in Nova Scotia, which is mostly rock underneath the soil, RMC just makes better sense, and will save you hours and hours of digging.
To get started you should measure the distance you’ll be running the wires, and gather up the following materials:
- A Hacksaw
- A pipe bender that will accommodate 3/4″ OD rigid conduit
- A fish tape that will reach through the piping
- A pair of pipe wrenches
- A drill and 1″ bit
- Wire cutters and strippers
- The proper length of Rigid Metal Conduit
- A length of standard (not solid) wire
- A spade shovel and/or mattock for digging
Now that you’ve gathered your tools, it’s time to get to work! The first step is to plan and dig the trench. Shorter and less bends is best, but you’ve also got to consider where the line will enter the house to draw power. Start with the house end, and bear in mind you can’t have more than a total of 360 degrees in bending over the course of the total line to meet code. Once you’ve planned and measure your route, pick up the Rigid Conduit to length, and add 10 feet to the wire to make sure you have plenty.
Drill the hole in the house first to ensure everything will work, then start digging a trench from the house to your shed. Use a narrow spade shovel or a mattock to do the digging. Also, a tarp set beside the trench to pile dirt on can save you having to rake out the grass later.
Now that you’ve got your 6″ trench dug, it’s time to mount the metal boxes and ‘LB’ connectors on both sides of the run. Start by drilling a 1″ hole in the walls to mount into. A junction box is installed inside, and the ‘LB’ outside, connected with EMT and conduit connectors. The RMC threads directly into the bottom of the ‘LB’ box.
Once the boxes are installed, it’s time to run the RMC. Start by bending it on one end, and then keep adding 10′ lengths outwards to the shed. Once you reach the end, bend it and cut it to fit with a hacksaw. Be sure to allow 3/4″ for the compression connector to attach it to the LB.
Now it’s time to run the wire! Remove the covers from your LB units, and grab your fish tape. If you are using a 15 amp circuit, use THWN-2 14 gauge wire, and if it’s 20 amp, use THWN-2 12 gauge wire. Be sure to leave 2 feet of wire on either end so you’re sure not to run shy. Once the wire is in, connect it to the circuit inside your home and a GFCI outlet in the shed. This way, if you ever overload it, you can simply reset the GFCI and not have to replace fuses or reset tripped breakers in the house. Wire the rest of the shed from the GFCI box to the outlets and lights in your shed.
And remember, if you need assistance at any point, call the professionals. Many people dig the trench and call a electrician to run the wires. Here at Flinn Electric, we’d be more than happy to assist you in bringing power to your shed or yard! A few hours of work, and you can kiss those annoying extension cords goodbye forever!