How To Short Out a Pool Motor Capacitor


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Capacitors by design store energy and in pool motors this energy can sometimes cause dangerous shock even after you have turned off the power to the motor. Before you work on the electrical side of a motor, you should ensure that this energy is dissipated. This guide shows you how to safely short out the residual energy in a pool motor capacitor after the pump power has been turned off. Note: Some motors have two capacitors, a run capacitor and a start capacitor. To be safe, you should short out both capacitors before working on the electrical circuits of the motor.

Step by Step


Step 1

TURN OFF POWER - Turn off the power to the pool pump. For maximum safety turn the power off at the circuit breaker.

Step 2

LOCATE START CAPACITOR - The pool pump Start Capacitor is almost always under the cover on the electrical end of the motor - where the power cord goes in. It provides an extra boost in power when the motor first starts up. The Start Capacitor will generally be rated at 50-400 MFD and 125 or 250 VAC.

Step 3

LOCATE RUN CAPACITOR - The Run Capacitor helps the motor run more efficiently during operation. It is almost always located under a bump cover on top of the motor. The run capacitor will generally be rated at 15-50 MFD and 370 VAC.

Step 4

REMOVE COVER - To gain access to the start capacitor, unscrew the two cover screws and remove the cover.

Step 5

LOCATE CAPACITOR LEADS - The end of the screwdriver is pointing at the leads of the Capacitor. There are three leads. For this motor two leads are yellow and one, going to the switch, is white with a red stripe.

Step 6

SHORT OUT LEADS - In rare cases a capacitor has been known to explode when shorted out. Wear gloves and eye protection and lay a cloth over the capacitor before you short it out. To short the capacitor place an insulated screwdriver across the three leads of the capacitor. Wiggle it around to make sure you contact all three leads.

Step 7

SHORT RUN CAPACITOR - After you have shorted out the Start Capacitor, repeat the process to short out the Run Capacitor, if applicable.

Step 8

CONTINUE REPAIR - Once the Capacitor(s) residual energy is released, you can continue work on the motor's electrical circuit.


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 Posted: 2/5/2018 

Susan - Thank you for your comment. I will correct the phrase "use an isolated screwdriver" to "use an insulated screwdriver"

 Posted: 2/3/2018 

Shouldn't directions read, "use an INSULATED screwdriver"?

InyoPools Product Specialist  Posted: 7/9/2015 

capacitor - Yes, the capacitor will still work after being shorted out. You are just releasing any built up charge.

Anonymous  Posted: 7/9/2015 

Hi, Once a capacitor is intentionally shorted, does it need to be replaced or will it work when powered back? Thanks, Sam