Wiring a Greenhouse

Wiring a Greenhouse
Written By
Danny Donahue
Danny Donahue
Published: Mar 20, 2011
Updated: Nov 20, 2021
3 minute read

Step 1

Lay out your flexible conduit on the ground. Cut each piece 3 feet longer than you need it to be with your tin snips to compensate for adjustments.

Step 2

Push the tip of the fish tape through the conduit. Hold the tip of the fish tape against the side of the last 3 inches of ROMEX®. Attach the fish tape to the ROMEX® with electric tape.

Step 3

Pull the fish tape slowly through the conduit to draw the ROMEX® through the flexible tubing. Pull the ROMEX® 3 feet past the far end of the conduit and cut the wire with your tin snips.

Step 4

Remove the electrical tape to free the ROMEX® from the fish tape. Pull ROMEX® through every piece of flexible conduit that you will need for the job leaving 3 feet of ROMEX® hanging past both ends of each piece. Roll up your fish tape in its housing and store it for future projects.

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Step 5

Mount your switches, fixtures and outlets to the exposed studs in your greenhouse. Use the Phillips-head bit on your drill to drive a galvanized screw through each of the retaining holes in every piece you wish to attach.

Step 6

Disassemble each of the fixtures and slide the end of the ROMEX® through the knockout hole in the back of the junction box. Pull the wire until the conduit is secure in the clamp mounted on the outside of the junction box. Tighten the retaining screw on the clamp with your screwdriver to lock the fixture in place.

Step 7

Slit the rubber armor on the outside of the ROMEX® with your razor knife. Pull the sheathing back and trim off the excess. Snip each wire to fit inside of the box and strip the individual wires with your wire stripping tool.

Step 8

Loosen any brass retaining screws on the side of the body of the inner workings of the fixture. Wrap the stripped end of each black wire around its own brass retaining screw. Tighten the screws to hold the wires in place.

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Step 9

Loosen the silver retaining screws on the side of the fixture. Wrap the stripped end of a white wire around its own silver screw. Tighten the screws to hold the wires in place.

Step 10

Connect the bare ground wires to the grounding screw in the back of the junction box. Reassemble the fixture being careful not to damage the wiring.

Step 11

Check the breaker box in your house. Be sure that the breaker hooked to the electric wires running to your shed is turned off. Strip the end of the black and white wires on the ROMEX® running to the shed.

Step 12

Hold the white wire running to the shed with the white wire running from the shed. Twist a wire nut onto the two wires to bind them together. Wrap electric tape around the wire nut and 6 inches up the wires to complete the splice.

Step 13

Connect the black wires and ground wires at the main junction. Attach any other splices necessary inside of the greenhouse. Turn on the breaker in the house and flip each switch in the greenhouse to check every circuit.

Tips

Some greenhouses may have PVC, composite, or metal wall supports. Use the proper fastener for the job when attaching conduits and fixtures to your greenhouse.

Warnings

Work gloves and safety glasses are required when working with hand tools.

Be sure that everyone is aware you are working on electrical circuits. Tell everyone on the property that they may not touch the breaker box until your project is complete.

Photo Credits

Jupiterimages/BananaStock/Getty Images

Danny Donahue

After learning electronics in the U.S. Navy in the 1980s, Danny Donahue spent a lifetime in the construction industry. He has worked with some of the finest construction talent in the Southeastern United States. Donahue has been a…

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