SESKStuff Everyone Should Know
SESK: Stuff Everyone Should Know · sesk.info/elec-gfci-6ma

A Class A GFCI trips when ground-fault current is at least how many milliamperes?

Class A GFCIs trip at 6 mA or more.

Start playing free

  1. 30 milliamperes
  2. 60 milliamperes
  3. 6 milliamperes ✔

Why: A Class A GFCI watches for current that goes out on one conductor and does not return. It trips at 6 mA or more, far below what would trip a breaker.

Huh, didn't know that: A special-purpose GFCI, used on circuits over 150V to ground, trips at 20 mA instead.

The dad joke
How did Mr. Power react after flinging off the electric charge he had on him? He was ex-static!
Like this card?
Play the game

References

Answer: 6 milliamperes. A Class A GFCI watches for current that goes out on one conductor and does not return. It trips at 6 mA or more, far below what would trip a breaker.

  1. EC&M: Top Changes to the 2023 NEC (Mike Holt) ecmweb.com/national-electrical-code/article/21254614/top-changes-to-the-2023-national-electrical-code
    for circuits rated not over 150V to ground, with a trip-open value of 6mA
    Checked 2026-10-10.
  2. EC&M: Branch Circuits Part Two (Mike Holt) www.ecmweb.com/national-electrical-code/code-basics/article/20889225/branch-circuits-part-two
    If the difference between the two is greater than 4 to 6 milliamperes, the circuit is interrupted.
    Checked 2026-10-10.

Think this answer is wrong? Tap "Challenge this answer" on the card in the game and tell us why.

Test yourself in the game

Trades & ShopAt a minimum, how often should you test a GFCI?Trades & ShopOn a construction site, what may OSHA accept instead of GFCIs to protect workers?Trades & ShopAn arc flash can reach temperatures of up to about how many degrees Fahrenheit?

That's stuff everyone should know.