0
\$\begingroup\$

I noticed the tip of my soldering iron is case grounded. I understand the GFCI compares voltages and trips if there is a difference (in the millivolt range). If the thermocouple generates a small amount of voltage, can't it trip the GCFI? Moreover, what does the GFCI use as a voltage reference?

\$\endgroup\$
  • 2
    \$\begingroup\$ It's not voltages that the GFCI/RCD is measuring, it's currents. It trips if there's a difference in the currents on the live and neutral wires. \$\endgroup\$ – Hearth Feb 5 at 17:52
  • \$\begingroup\$ Could you post a model number of your soldering iron, please? I'm curious about its grounding. \$\endgroup\$ – Nick Alexeev Jun 22 at 22:47
1
\$\begingroup\$

I understand the GFCI compares voltages and trips if there is a difference (in the millivolt range).

Actually, the GFCI compares current (in the "line" and "neutral" wires) and trips if there's a difference of more than a few mA.

If the thermocouple generates a small amount of voltage, can't it trip the GCFI?

No, the thermocouple (if your iron even has one) would be unrelated to this.

Moreover, what does the GFCI use as a voltage reference?

A GFCI does not need a great deal of precision, so it probably just uses a diode junction as a voltage reference.

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.