Capacitor and Stored Electrical Energy
Construction and general industry · Ver en español
Talking points
- Capacitors store electrical energy and can deliver a dangerous or lethal shock even after the equipment is unplugged and locked out. Large capacitors in VFDs, UPS systems, and power factor correction units can hold a charge for hours.
- After de-energizing a circuit containing capacitors, wait the manufacturer-specified discharge time before touching any components. Some systems have automatic bleed resistors; others do not.
- Verify discharge with a voltmeter before touching capacitor terminals. Use a discharge tool if the capacitor has not self-discharged within the expected time.
- Short-circuit the capacitor terminals to ground with an insulated shorting bar after discharge to prevent re-energization from residual charge or induction.
- Even small capacitors in electronic equipment and power tools can store enough energy to cause a painful shock and startle reaction — which can lead to a secondary injury from a fall or recoil.
Ask the crew
Does any of the equipment we are working on today contain capacitors — and do we know the discharge procedure?
Standards this talk is built on
A toolbox talk is a short safety briefing. It supports the training a standard requires; it does not replace it.
Run this talk with your crew and keep the record
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Sign-in sheet
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| Name | Signature | Date |
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