Type: Adjustable Auto-Cycling
Vacuum: Electric Pump
Page: 9 of 11
Attach the Electrical Box
Parts used in this section:
Wood screws #8 x 5/8"
2 Romex connectors
Wrench or pliers
Remove two of the "knockouts" from the electrical box to allow for the wiring of the unit. You can remove any two of these knockouts depending on where your wires are running. In this example, I removed the two that are at the far ends of the box.
Attach the romex connectors to the utility box where the knockouts were removed.
Attach the electrical box to the upright on the carrier with two to four wood screws as shown in the picture below.
If the pump you are using comes with a capacitor, now is good time to attach it to the carrier.
Wiring Preface You don't need an electronics degree to successfully wire the system but you must be aware of the essential practices and principles of safety when working with 120 volts. Do not proceed to wire this system without the help of a certified electrician if you are uncomfortable working with electrical components, or if you are unfamiliar with the risks associated with electricity. Be sure to read, understand, and agree to the terms and conditions found on this page before proceeding.
If you are soldering the wires to the vacuum controller, be careful not to damage the vacuum controller by over-heating the tabs. Allow the soldering iron to reach full heat before you begin. Then apply solder to the common and normally closed tabs. Next apply solder to the wire ends. Lastly, reheat the wire ends onto the tabs. This last step should not require any additional solder. Be sure to adequately insulation any exposed wire near the terminals.
Or, if you opt to use crimp-on connectors, simply strip off 1/4" of insulation and insert the wire into the connector and crimp the plastic area of the connector with a pair of pliers.
Vacuum Pump Amperage The vacuum controller included with the EVS kit can handle up to 10 amps at 120v AC. The label on most vacuum pumps will display the running amperage but not the start up amperage. The spike in electricity when the pump starts up can greatly exceed the running amperage. In fact, rotary vane pumps can require three times more amperage at start up over the running amps. Damage to the vacuum controller will occur if the start-up amperage exceeds that which the vacuum controller can handle.
120v AC Vacuum Pump Drawing Less Than 10 Amps At Start Up
This wiring method is specific to the 5 CFM vacuum pump that I used for this build but it may also apply to other pumps. If you have purchased a rebuilt Thomas vacuum pump from VeneerSupplies.com, please refer to the wiring information found on the PDF version of the kit instructions.
If your pump has a power cord and plug-end attached, the easiest way to proceed is by cutting the cord leaving enough wire to reach from the vacuum pump to the utility box (plus 6 inches).
To access the individually insulated wires inside the power cord, remove 3 inches of the black insulation on the wire end that remains attached to the pump. Insert this stripped section of wire into the utility box so that the 3 inches of individual wires are easy to connect to the rest of the system. Do not tighten the screws on romex connector that holds this power cord in place yet.
Measure the distance between the vacuum controller and the utility box. Add 6 inches to this measurement and cut this length from the left-over power cord that was cut off the pump in step 1. Set this piece of wire aside. It will be used in a few minutes.
Remove 3 inches of the black insulation from the remaining piece of wire from step 1 (the wire with the plug end). Insert this stripped section of wire into the utility box so that the 3 inches of wire are easy to connect to the other system wires that will be in the box.
Pull one of the wires from the Mac valve into the utility box through the romex connector mentioned in step 2 above. The Mac valve wires are non-polarized so either wire is fine to use for this step.
Attach this wire and the white (neutral) wire from the pump to the white wire on the main power cord with a wire nut. Remove 1/2" of insulation from each wire to do this.
For this step, you will need the short piece of power cord from step 3. Remove 3 inches of the black power cord insulation from both ends of this wire.
With solder or a crimp-on connector, attach the black wire to the common tab on the vacuum controller. To get to this tab, remove the plastic lid on the vacuum controller.
Attach the white wire to the normally closed tab on the vacuum controller with solder or a crimp-on connector.
Insert the other end of this small section of the power cord into the utility box.
Insert the remaining wire from the Mac valve into the utility box. Attach this wire and the black wire from the vacuum pump to the white (switched hot) wire from the vacuum controller. Twist these three wires together and attach a wire nut.
Now tighten the screws on the romex connector.
Attach the remaining black wire from the short section of the power cord to one of the terminals on the light switch. Do not use the ground terminal.
Attach the black wire from the main A/C power cord to the remaining terminal on the light switch. Again, do not use the ground terminal.
If your power cord comes with a ground wire, you can attach it first to the light switch on the electrical box. Then route this wire to the grounding screw or wire on the pump (if the pump has one).
Remove the "ears" from the light switch and attach the switch to the utility box. Then attach the light switch plate.
120v AC Vacuum Pump Drawing Less Than 10 Amps at Start Up
For use with Thomas 3 CFM vacuum pumps
If your vacuum pump draws more than 10 amps at start up, you will need a relay with a 120v AC coil and contacts rated for at least 30 amps @ 120v AC. The relay is available by clicking here.
There are only three differences between this wiring situation and the one shown above.
The vacuum controller is now controlling the relay only.
The vacuum pump and Mac valve are now powered through the relay. The relay gets its power feed from the hot wire on the light switch (see the blue line shown below).
If you are using a vacuum pump that draws more than 15 amps, you will need to upgrade to a heavy duty light switch.
When the wiring is complete, be sure to put electrical tape over the screw terminals on the top of the relay.
Option 3: 240v Vacuum Pump
Due to safety and liability issues associated with 240v electricity, I do not support this type of configuration. I can not provide assistance, instructions, or diagrams for building a high voltage system. Please consult a certified electrician before purchasing and/or building a 240v system.
Several surplus centers are offering inexpensive 240v pumps. The Gast 0522 nd 0523 pumps are notoriously troublesome. You have to ask yourself if it's worth saving $35 for the hazard of a system wired for 240v.