JFletcher
Senior Member
- Location
- Williamsburg, VA
Customer called about installing a Broan QT model fan (4 function) in place of the old 2 function fan (light and fan). I've been looking over the specs for this fan and have a few questions:
1) I know I'll need a dedicated 20A circuit for this model (1500W), and pulling that is no problem. However, the fan needs 4 switchlegs, a neutral, and a ground. Is there anything such as 12/5 NM? Cant seem to find it - would 2 runs of 12/3 work here (would rather not use MC and conduit is out of the question)? I know if I use 2 cables I have to have 2 neutrals instead of 1, and they cannot be joined together.
2) At what CFM range do standard fans switch from 4 to 6" ductwork? Some of the QT series require 6" (not sure which one customer has). Short of going all the way out there or having the HO pull the existing fan for a measure, is there any way to tell beforehand? Also, if the ducting is mismatched, is there any code (NEC, building, or otherwise) compliant way to install a hub/reducer from fan outlet to the existing ducting?
3) On units 1400W total or smaller, if the mfg says to use a 15A circuit, am I stuck with that or may I use a 20A?
4) Provided I pull a new dedicated circuit (20A) to the fan, may I use more than one circuit to power it? Thought being I could use the existing 14/3 to the old fan/light to power the light/nightlight, and use one new 12/3 from a dedicated circuit to power the fan and heater. I could remove the existing fan and light switches and replace them with a timer control for the heater and a 3 function switch, or a 4 function switch if there is a just a single combination switch there. Does anyone see a problem with this?
1) I know I'll need a dedicated 20A circuit for this model (1500W), and pulling that is no problem. However, the fan needs 4 switchlegs, a neutral, and a ground. Is there anything such as 12/5 NM? Cant seem to find it - would 2 runs of 12/3 work here (would rather not use MC and conduit is out of the question)? I know if I use 2 cables I have to have 2 neutrals instead of 1, and they cannot be joined together.
2) At what CFM range do standard fans switch from 4 to 6" ductwork? Some of the QT series require 6" (not sure which one customer has). Short of going all the way out there or having the HO pull the existing fan for a measure, is there any way to tell beforehand? Also, if the ducting is mismatched, is there any code (NEC, building, or otherwise) compliant way to install a hub/reducer from fan outlet to the existing ducting?
3) On units 1400W total or smaller, if the mfg says to use a 15A circuit, am I stuck with that or may I use a 20A?
4) Provided I pull a new dedicated circuit (20A) to the fan, may I use more than one circuit to power it? Thought being I could use the existing 14/3 to the old fan/light to power the light/nightlight, and use one new 12/3 from a dedicated circuit to power the fan and heater. I could remove the existing fan and light switches and replace them with a timer control for the heater and a 3 function switch, or a 4 function switch if there is a just a single combination switch there. Does anyone see a problem with this?