On Thursday, May 14, 2020 at 2:04:38 AM UTC-4, Deguza wrote:
I have an older home.

I would like to replace some of the two-hole receptacles with three-hole ones.

A friend told me to use GFCI, or better a GFCI receptacle.

(I also see a GFNT1 type. I have no idea what that is...)

What do you think?

Thanks!

Deguza

Depends what you're most worried about and where the receptacle is located.
A GFCI protects against ground faults, which is important since with a two
prong receptacle you have no ground. If there was a short from the hot
wire to the metal case of a toaster or similar, the metal case would become
energized and if you touched it while standing on a wet floor or touching
a grounded appliance or water pipe, you could get shocked. With a GFCI,
it will cut off the power when it detects a fault current of just a few
miliamps, way below a harmful level. A GFCI receptacle will also protect
downstream receptacles that are daisy chained to it, if wired in correcly.

AFCI is to detect and trip on arc faults, an example would be an appliance
cord under a rug that's worn or wires some rodent has chewed, etc.
An AFCI is most useful if it's in the panel, since it would then protect
the whole wiring run on that circuit. At a receptacle, it will only
protect what's plugged in.

For sure if it's a wet location, basement, possibly used for extension
cords run outside, kitchen, bath, etc, I would go with GFCI. I'd go
with that for any location, unless there is reason to believe AFCI would
be more important. For the worry warts, I guess there are ones that will
do both GFCI and AFCI.

The GFNT1 thing, I didn't know about those. Looks like that's the newest
GFCI that now includes automatic, periodic self-test, while the previous
ones had a test button. So, I'd go with those for GFCI, unless they cost
significantly more.