0

I want to install a ceiling fan where a ceiling light currently exists in my garage. The box for the current light has only two wires coming in however: a black & a white (no ground - looks like original wiring from 1950's). My question is how can I ground the ceiling fan if I install it in this 2-wire box location? Can I run the ground wire from the ceiling fan to a separate nearby ceiling light box which does have a ground wire coming into it? This nearby ceiling box is on the same circuit (i.e. both the ceiling fan and the nearby electrical box are controlled by the same circuit breaker). I realize I would of course need to first install a ceiling fan rated electrical box to attach the ceiling fan to, but can I ground the ceiling fan to this nearby ceiling light box which is properly grounded back to the circuit breaker panel?

  • 1
    Is the existing wiring in metal conduit with metal boxes? If so, that will (typically, not always) function as an effective grounding path. – manassehkatz May 5 at 20:04
  • What edition of the NEC is your locality on? – ThreePhaseEel May 6 at 0:40
  • @manassehkatz Believe it or not, when I removed the light fixture to try and replace it with my ceiling fan, there was NO electrical box at all. The light fixture was screwed into a piece of hard cardboard, and the cardboard was simply resting up on the ceiling drywall. The black & white wires had a cloth type sheathing around them and were connected to the light fixture. So bottom line is I'm installing a new metal ceiling fan rated box. But this box is not grounded. – Peter May 6 at 3:22
  • @ ThreePhaseEel I don't know what edition of the NEC, but I'm located in Florida. – Peter May 6 at 3:24
  • 1
    As I understand it, it does NOT need to be the same circuit, but if it is on a different circuit then the ground path has to be big enough the entire distance (e.g., grounding a 20A circuit using the ground path of a 15A circuit would not work unless the 15A ground path (e.g., metal conduit) happened to be adequate for a 20A circuit. – manassehkatz May 6 at 3:54
3

Yes you can

Recent NEC editions allow you to run a retrofit ground wire (equipment grounding conductor) from an ungrounded box/circuit to a grounded branch circuit's ground wire, provided the donor circuit has a large enough ground wire to be a suitable ground for the circuit being retrofitted. (For instance, if you are grounding a 20A circuit this way, the donor circuit would need to have a 12AWG or larger ground wire.) The permission for this is given in NEC 250.130(C):

(C) Nongrounding Receptacle Replacement or Branch Circuit Extensions. The equipment grounding conductor of a grounding-type receptacle or a branch-circuit extension shall be permitted to be connected to any of the following:

(1) Any accessible point on the grounding electrode system as described in 250.50

(2) Any accessible point on the grounding electrode conductor

(3) The equipment grounding terminal bar within the enclosure where the branch circuit for the receptacle or branch circuit originates

(4) An equipment grounding conductor that is part of another branch circuit that originates from the enclosure where the branch circuit for the receptacle or branch circuit originates

(5) For grounded systems, the grounded service conductor within the service equipment enclosure

(6) For ungrounded systems, the grounding terminal bar within the service equipment enclosure

Informational Note: See 406.4(D) for the use of a ground-fault circuit-interrupting type of receptacle.

Furthermore, since ground wires do not need to run with the circuit they are grounding as per NEC 300.4(B)(2):

(2) Grounding and Bonding Conductors. Equipment ground‐ ing conductors shall be permitted to be installed outside a race‐ way or cable assembly where in accordance with the provisions of 250.130(C) for certain existing installations or in accordance with 250.134(B), Exception No. 2, for dc circuits. Equipment bonding conductors shall be permitted to be installed on the outside of raceways in accordance with 250.102(E).

, you can simply run a bare 14AWG wire from the new ceiling fan box, through the ceiling, to the "donor" box, bring the wire into the box, and connect it to the existing ground wire bundle there.

  • Thank you for the information. This is exactly what I wanted to do; run a bare ground wire from the new ceiling fan box, through the ceiling, and into the grounded "donor" box. By the way both the new ceiling fan box and the donor box are on the same 15A circuit so this should work nicely with the 14AWG wire I already have. – Peter May 6 at 4:27
  • Is it OK to use just BARE copper ground wire running through the ceiling to the donor box? As opposed to say running 14-2 Romex, using the ground wire on that to make the grounding connection between the ceiling fan box and the donor box, and capping off the black/white wires in the Romex on both ends. Reason I ask is that at least the ground wire in the Romex is sheathed as opposed to just bare copper wire. – Peter May 6 at 13:59
  • @Peter -- yes, you can just use a bare copper ground wire running through the ceiling. – ThreePhaseEel May 7 at 0:04
  • Thank you for the response and all of your insight! – Peter May 7 at 1:30
0

Why are you using the existing wiring to install a new fixture? This isn't code compliant and it's saving $10 to do it in a manner that's unsafe... Run new wire that's grounded and stop trying to cut corners.

  • 1
    (a) It may very well be code compliant - there are pros (not me) who will determine that; (b) while in this case it may not be a big deal to run a new cable, there most definitely are times where running a retrofit ground (if permitted) is a lot easier than running a new cable. – manassehkatz May 6 at 3:36
  • If running new wire that's grounded only costs $10 then I completely agree. But my understanding is that running new wiring back to the breaker box is costly. – Peter May 6 at 3:39

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.