Switch Box - Canadian Woodworking Magazine


Switch Box

Anything that makes your time spent in the shop safer and more enjoyable is worth looking into. Many shops are equipped with a router, mounted in some sort of a table. While this arrangement vastly increases the utility of the router, it can also place the on/off switch in an awkward position. If you use a shop vac or dust collector with your router table, it adds yet another switch. A popular modification is to build a switch box that turns your shop vac on when you turn your router on.

You can obtain the parts that you need to connect your router table to a shop vac at most building supply outlets, such as Home Hardware. Assembly is fairly straight forward. Purchase an adequate length of 14/3 electrical cord. I found that since my router table is portable, about 25’ of cord is adequate. With that length, I can locate it anywhere in the shop and still have enough cord to pass it behind other equipment so that I don’t risk tripping on it.

Begin by installing a male plug (also called a 'cord end') on one end of the electrical cord.

The other end will be connected to a receptacle box. There will be several pre-punched knock-outs in the receptacle box, and after considering your final mounting location, remove the appropriate one. Using a locknut, secure the strain relief connector to the box. Strip off approximately 8" of the cord insulation, and secure it in the strain relief connector. 

Switch to turn on router and vac simultaneously

Most switches and receptacles are designed for use with solid wires, so use a piece of regular 14/2 electrical cable for these connections. Using a wire connector (also called a marrette), connect a short length of solid #14 black conductor to the stranded black wire. Then attach the other end of the solid wire to one of the screws on the switch terminal. From the other terminal on the switch, run a black wire to the ungrounded (hot) side of the receptacle. Most manufacturers indicate which terminal this is, either with a brass coloured screw, or some form of embossed writing.

Attach a short length of solid white wire to the stranded white wire and attach this to the neutral side of the receptacle, which typically has a silver coloured screw. If in doubt as to which screw to use, look at the front of the receptacle. The screw with the wide slot is neutral and is always on the left. The screw with the narrow slot is hot, and is on the right side. To assure proper grounding of this receptacle, cut two 6" pieces of bare copper and twist the two solid pieces together with a pair of pliers. Attach these to the stranded ground wire. Attach one of the solid ground wires to the ground screw in the box, and the other one to the ground screw on the receptacle.

At this point, mount the box in a convenient location. A pair of wood screws through the holes in the back of the box works best. You’ll have to trim the plaster ears on the switch and receptacle to mount them to the cover plate. After mounting these to the cover plate, remove the appropriate knockouts and mount the cover plate to the box. As you push the wires into the box, make sure that they are not pinched and that the bare ground wire doesn’t come into contact with any of the terminals on the switch and receptacle.

By moving the switch to a more accessible location, it will also be more prone to being accidentally turned on if it is bumped or snagged. Add an additional level of safety by attaching your collet wrench to the very end of the power cord of the router. That way, in order to use the wrench, you will need to unplug the router.

Some routers with speed control and electric braking use multi-pole on/off switches to control these advanced features. You may find that when you install a remote switch, these functions may be disabled. I use a Makita 3612BR and by using a remote switch, the electric brake is disabled. To check compatibility is to turn the (table mounted) router on while it is unplugged and then plug it into an outlet and observe its functions. Then unplug the router to observe the braking function. If in doubt, consult the manufacturer.

Wiring parts

Cord or cable?
Electrical 'cord' is referred to as SOW cord. The cord will have a flexible rubber jacket and stranded wire. Electrical 'cable' on the other hand, will have a ridgid plastic jacket and solid wires. This cable is also referred to as NMD cable. The wire in both cords and cables are properly referred to as 'conductors'. You’ll want to be careful when removing the outer jacket; depending on the type of cord you buy, it may not be that thick and you could easily cut into the insulation covering the individual conductors. To provide mechanical strain relief, cord ends rely on the cord insulation in conjunction with internal ribs (which look like strands of twine); remove only the insulation required to maintain the integrity of this design.


Michael Kampen