I'm working on a project that uses 1700VDC provided from a 220V:1200V isolated toroidal transformer, bridge rectifier and filter cap. I have no experience with high voltages, so I'd like to ask you some questions regarding safety. So far, I will:

  • Use insulating gloves Class 1 + leather protector glove.
  • Use Emergency button.
  • Use warning lights
  • De-energize circuit before taking measurements.

My questions:

  • Since the transformer is isolated, I don't need to use insulating boots right? Should I be concerned with capacitive coupling that is mentioned here?
  • Should I ground/earth any part of my circuit? How about the equipment frame metal parts?
  • Should I use RCD or circuit breaker only?
  • Am I missing something?
  • 1
    \$\begingroup\$ Add a fuse or Polyfuse (PTC) and maybe NTC surge reduction. 1.2kV insulation air gap >2mm. Beware of Safety with power off charge from memory capacitance or add discharge load. \$\endgroup\$ Jul 22, 2020 at 2:47
  • \$\begingroup\$ How much current can your 1700VDC supply provide? \$\endgroup\$
    – marcelm
    Jul 22, 2020 at 7:12
  • \$\begingroup\$ @marcelm the transformer is 800VA. So, huge currents. \$\endgroup\$
    – Rohde
    Jul 22, 2020 at 20:17

1 Answer 1


Take every precaution possible as 1700 VDC will have no mercy on you. Capacitive leakage in the transformer means isolation is not that safe. Touch the high voltage and it will zap you, possibly burn you. Get used to wearing those gloves.

Do not earth ground as it makes it an unisolated supply.

If you always wear safetygloves the boots are not needed. When I was working with 600 VAC to 4,160 VAC surge protection devices I held a dead-mans switch in my left hand while testing live equipment.

Use a Tektronix 40 KVDC HV probe if measuring the high voltage. Do NOT put your DVM on a metal table.

Keep metal items away from you and the 1700 volts. Keep a 3 foot / 1 meter clear space around you. Nothing to trip on or bump into. No water on the floor or high humidity. NO ONE gets to come close to you while the HV is on.

The main HV switch should have lock-out tag-out procedures where you can padlock it OFF, or use a bar to trap it in a OFF position.

HV safety protocols are tedious, but you live to talk about it.

  • \$\begingroup\$ Can you elaborate on the dead man's switch ? I always thought that when electrocuted, one can't let go of things (in this case, the switch). \$\endgroup\$
    – AJN
    Jul 22, 2020 at 8:07
  • \$\begingroup\$ The arm being electrocuted freezes, but the other arm can jerk loose of a dead-mans switch. The arm that was shocked may not work for a day or so, and it is very painful to be shocked by high DC voltages. \$\endgroup\$
    – user105652
    Jul 22, 2020 at 8:22

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