I recently moved to a new house and I am planning to put cieling fans on the second floor thru attic. There are 4 rooms. One cable already running in attic is powering a 40 W light and attic exhaust fan. Can I add 4 more cieling fans to it OR do I need to run new cable?

Thanks.

 

Please provide more information.

What do you mean by attic fan? A permanently installed fan, or a moveable fan? A hard-wired fan or a cord and plug connected type? What size wire feeds the fan?

What about these ceiling fans? Fans only, or fans and lights? If lights, what size bulbs (wattage) and how many per unit? What size fan motor?

The short answer to your question is probably not. Code most likely requires that the attic fan be on it's own circuit, so even the 40 watt light being on that circuit may not be legal (although it may have been at the time of installation). As for adding the fans, the combined needs of the fans (and any lights they have) added to the requirements of the attic fan may be too much for a single circuit.

 

I don't believe there is any code requirement for attic fans to be on a dedicated circuit (though local codes may in some cases.)

The key question is, how big is that attic fan? How many amps does it draw? and does it run continuously?


Putting for fan/light combos on the same circuit is generally not a problem. But, the power draw of the fan may be. If it's a "whole house" fan, then you'll probably overload the circuit with the 4 ceiling fans. If it's strictly a thermaticaly controlled exhaust fan, then you may well be OK.

 

I would suggest calculating whether you can do this or not rather than guessing. Firstly check the size of the breaker to this circuit in your breaker box. This will usually be either 15 amps or 20 amps. Next verify the current draw of the attic fan (may be stamped on the fan or you can calculate by dividing the power by the voltage). Your light will consume 40/120 = 333mA. Add this to the current draw of the fan plus all other items on this circuit. Finally get the current draw of the fans you plan to add and add it to the total. The total current should be less than that of the circuit - ideally 2 to 3 amps less in case of overload due to surge. If this is the case you can add the fans. If not you will need a new circuit or use another circuit.

Hope this helps

Ravin