How to build a hybrid extension cord/outlet strip.
DANGER: This project involves household outlet voltage. DO NOT ATTEMPT IF YOU ARE NOT FAMILIAR WITH 120V HOUSEHOLD WIRING.
When the project is completed you have an adaptable extension cord. I used 5 outlet boxes, you can use as many or as few as you want, just change the length of the cord and parts count accordingly.
Step 1: Required Tools
To build this cord you will need:
A set of wire cutters
A wire crimper
A wire stripper or knife (or both)
A small and large flat blade screw driver
Pliers (needle nose or regular) (not pictured)
To test this cord you will need:
A Digital Multi Meter (not pictured)
An Outlet Tester (not pictured)
Step 2: Required Materials
To build this you will need:
1x 25ft 14ga medium duty extension cord
10x duplex outlets (buy the contractor's pack)
10x entry cable clamps 3/8 inch (fits half inch hole)
5x metal electrical box
5x metal box cover
70x 16-14ga 4-6 stud spade lugs (buy the 100 pack)
Step 3: Box Prep
To prepare the box for use you will need to do the following:
1). Use a screwdriver to pop one of the small holes on the top and one on the bottom out.
2). Use the pliers to bend the small round cover until it breaks off.
3). Install the cable entry clamps into the holes. Orient them so the screws face sideways compared to the box (as seen in the pictures)
4). Build all of the boxes the same way.
Step 4: Wire Prep
This will be the most boring and tedious section of the project. Do not skip the steps of crimping the spade lugs onto the cable! You will have a much easier time using the cable with the lugs on it. This also gives the cable a more professional build.
1). Identify how far from the plug to the first box (about 10 feet for me). Measure that length from the plug and cut the cable.
2). Strip about 6 inches of the outer insulation from the cut end of the cable. Be careful not to damage the inner conductors.
3). Strip about 3/8 inch of the insulation off of the black, white, and green wires.
4). Place a spade lug on the stripped wire and crimp it on.
5). Measure about 2 feet from the receptacle end of the cable and cut.
6). Strip about 6 inches of the outer insulation from the cut end of the cable. Be careful not to damage the inner conductors.
7). Strip about 3/8 inch of the insulation off of the black, white, and green wires.
8). Place a spade lug on the stripped wire and crimp it on.
9). Cut the remaining wire into 4 sections that are about 2 feet long and 5 sections that are about 6-8 inches long.
10). Strip about 6 inches of the outer insulation from each end of the 2 foot cable. Be careful not to damage the inner conductors.
11). Strip about 3/8 inch of the insulation off of the black, white, and green wires.
12). Place a spade lug on the stripped wire and crimp it on.
13). Strip all of the outer insulation off of the 6-8 inch sections (you want only the black, white, and green wires).
14). Strip about 3/8 inch of the insulation from each end of the 15 short wires, then crimp a spade lug onto each end.
Step 5: Outlet Prep
Prepare the outlets for installation into the box
1). Remove the screws from the tabs.
2). Depending on the box that you choose, remove the mounting ears.
3). Attach a black and white wire to each outlet in pairs. Attach the black wire to the gold screw, and the white to the silver screw. Do not use the green screw yet. I attach the wires to the bottom screws on the first outlet and the top screws on the second outlet.
Step 6: First Box
This is the first box in the chain.
1). Take the cable with the plug end on it, and insert it through the "top" cable clamp on one of the boxes prepared earlier, then tighten the clamp evenly.
2). Insert a 2 foot jumper cable through the "bottom" cable clamp on the box, then tighten the clamp evenly.
3). Attach the black and white wires from the cables to a pair of outlets, one cable to each outlet.
4). Attach a green jumper with and the cable's green wire to the first outlet's green screw, then attach the same green jumper to the other outlet in the pair with the other cable's green wire.
5). Install the outlets onto the box cover using the hardware that came with the cover (mine came with screws and nuts).
6). Install the cover onto the box. NOTE: Depending on where and how you plan to mount the box, it might be worth not fully installing the cover at this time.
Step 7: Last Box
Now we build the last box in the series. I then build the intermediate boxes.
1). Insert a 2 foot jumper wire through the "top" cable clamp of the box, then tighten the clamp evenly.
2). Insert the receptacle end of the cable through the "bottom" cable clamp of the box, then tighten the clamp evenly.
3). Attach the cables to the outlets as you did for the previous box, including the ground wires.
4). Install the outlets on the box cover.
5). Install the box cover onto the box. NOTE: depending on where and how you plan to mount the box, it might be worth not fully installing the box cover yet.
Step 8: Intermediate Boxes
Now we assemble the intermediate boxes. These are very much like the first and last box, but you only use the jumper cables between the boxes.
Step 9: Checkout and Finished Project
Before you plug this into the wall, some basic safety checks.
You need a Digital Multi Meter (you do know how to use one, right?)
Using the OHMS settings, check for shorts between the conductors on the cable. Neutral to ground, neutral to hot, and hot to ground. If you find any, check all your work and repair the problem. Check that the metal boxes are connected ONLY to the ground conductor! YOUR SAFETY DEPENDS ON THIS CHECK!
If the unit passes the short check finish installing the unit where you want it, make sure all the covers are fully tightened down.
Plug the unit into power. If you pop the breaker you plugged into, check your work for shorts again.
Use an outlet tester to check all the outlets, including the cable receptacle. If the outlet tester shows correct wiring in all the outlets, you can use the project. If not, find the error and repair it before use.