Don’t Be “Shocked” if You’re Not Well Grounded
- Almost 500 people die each year from electrical accidents, mostly in the workplace, putting it among the top 10 causes of accidental death in the U.S.
- Approximately 80% of all injuries and fatalities caused by electrical accidents are not caused by the electric shock itself, but by the intensive heat, light and pressure blast caused by electrical faults.
- The blast made by vaporizing metallic components can break bones and damage internal organs.
Scary? Don’t be one of these statistics. One important factor in plant safety is proper grounding techniques. There is no faking it here, so make sure you are working with a licensed master electrician. Here are just a few important things to remember about grounding to protect both people and equipment:
- The ground wire must be sized the same size as the supply wires or one size smaller as a minimum. The three-phase power brought into a plant must also have a ground wire.
- Do not mix wires of different voltages in conduit.
- Never run any wires through an electronic control panel that do not relate to the function of the panel; electronic control panels should never be used as a junction box.
- Never allow field wiring to come in close proximity with the controller boards.
- Never add relays, starters, timers, transformers, etc. inside an electronic control panel without first contacting the manufacturer for specific instructions.
- Never run refrigerant tubing inside an electronic control panel (ammonia will destroy your electronics).
- If the electronic control panel has a starter built into the same panel, be sure to run the higher voltage wires as indicated by the manufacturer since EMI from the wires can interfere with the electronics if run too close to the circuitry.
- Never daisy-chain or parallel-connect power or ground wires to electronic control panels.
- Sensitive electronics require special grounding; ground impedance of one ohm or less may protect people from electric shock but may not be enough protection for electronic equipment. IEEE recommends a ground impedance to be less than 0.25 ohms for proper protection.
- Check all devices immediately after installation to verify proper wiring; receptacles should be checked to avoid common wiring errors such as reversed polarity or an open neutral.
- Check the manufacturer’s requirements, codes, and always hire a licensed master electrician for electrical work. It may save a life and it will almost certainly save your electronic equipment.
The bottom line is, we CAN protect ourselves and our workers from electrical accidents AND ALSO prevent costly equipment damage by using certified devices, testing equipment from reputable manufacturers, and keeping up to date on electrical codes. For specific code compliance information see http://www.neccodebooks.com or get the latest electrical codes from the NFPA online.
If your electronic equipment does get fried, we will be delighted to provide the industrial electronics repairs you need. We service virtually all electronics manufacturers. ACS Industrial Services’ tech team is here to help you. Click here to fill out a free repair quote form right now.
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