I have some confusion because on the one hand AFCI protection is not specified as needed in bathrooms by the NEC, but on the other hand the NEC does state that AFCI protection needs to be added when modifying or extending existing branch circuits when an additional outlet or device is added to a circuit.

So what would be required if I added an additional outlet on an existing branch circuit in a bathroom -- is AFCI protection required in this case since I am adding this additional outlet to an existing circuit or is AFCI protection not needed since the additional outlet is being added to an existing circuit in a bathroom?

If it's the second scenario and AFCI protection is not required, would it be wrong to add AFCI protection anyways (via an AFCI/GFCI outlet as the first outlet in this circuit)?

I am asking because I need to install an additional bathroom outlet in an existing circuit for a toilet bidet.


1 Answer 1


AFCI protection needs to be added when modifying or extending existing branch circuits when an additional outlet or device is added to a circuit

I believe this is intended to mean:

  • Replace an existing receptacle or device on an existing non-AFCI circuit - AFCI not required
  • Add a receptacle or device to an existing non-AFCI circuit that would require AFCI if it were a brand new circuit - AFCI required

This results in you not being able to avoid AFCI by simply always using existing circuits, but at the same time AFCI is required on existing circuits if it would be required in a new circuit.

So in your example, if you can (i.e., subject to any other constraints) make use of an existing bathroom circuit (so GFCI required but not AFCI for that circuit) to add your additional receptacles/devices then you do not need to add AFCI protection. If you did a similar thing (well, hopefully not a bidet) in a bedroom or other room where new circuits require AFCI protection, then you would need to add AFCI protection at that time.

  • 1
    Just so I understand, you're saying that since this existing circuit that I need to add a new outlet onto is in a bathroom, then AFCI protection is not required? Though as to my last question, would it be bad (i.e. violate code) to add AFCI protection to this circuit anyways? I find this issue confusing because the NEC does state that AFCI protection is required in bathrooms when extending or modifying branch circuits in the case of "dormitory units". So it seems like there is nothing particularly bad about having AFCI protection in bathrooms per se.
    – max mel
    Feb 7 at 2:27
  • Nothing bad about AFCI for bathroom circuits. My understanding is that a lot of NEC is a compromise - balance improvements in protection against injury/death and fire vs. cost. AFCI in particular mostly is done with a relatively expensive circuit breaker. GFCI can be easily done with a relatively inexpensive GFCI/receptacle. For a bathroom, the biggest factor by far is injury/death due to water + electricity, so GFCI has been required for a while and is highly recommended as an upgrade (e.g., my bathrooms ~20 years ago when I wasn't actually making any changes to those circuits). AFCI Feb 7 at 2:30
  • has a higher cost (generally) associated with it and simply doesn't have the same obvious safety benefits. AFCI can protect against a lot of things, but those are things that many homes will never have (chewed up wiring, loose wiring, etc.) Anyone who has had even a single GFCI "nuisance trip" (and I can think of a few in my home over the last several years) has easy proof that they avoided a potentially dangerous situation. But on new circuits and/or if you can afford it? Sure. Arguably a few instances are worth avoiding AFCI unless required (refrigerators) and some have specific exceptions Feb 7 at 2:34
  • such as fire alarm panels because the balance of "what if there is a nuisance trip that causes vital equipment to be offline when truly needed" outweighs "what if AFCI would have caught a real problem". But for bathrooms, nothing really wrong with it. Dormitories are a somewhat different setup, which is why the rules are a little different. (and I know colleges typically have strict rules - that get ignored by students - about what devices they can plug in to receptacles in dorm rooms - same problem.) Feb 7 at 2:36

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

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