How many recessed lights can I put on a 20 amp breaker using 12/2 romex? On a 15 amp breaker?

will use 65 watt bulbs.
distance to farthest light from breaker box is 33 ft

 

A 20 amp circuit can have a continuous load of 1920 watts. A 15 amp, 1440 watts.
The size lamp you will be using is irrelevant. You have to figure the maximum wattage rating for the fixtures you will be using.

 

Answer I was looking for!

 

Speedy,
Are you saying that a branch circuit has to be sized by the load that could possibly be on it?

 

what about the wiring. Could I use 14/2 instead of 12/2?

Can I use any 14/2 with a 20 amp breaker? Say bring power to the center of the lights with 12/2 and then run 14/2 off both sides?

Thanks again

 

Did I say that?

Seriously, just beacuse he is using 65 watt lamps in an H7 with a 310P trim for instance doesn't mean you can figure the circuit for it. The cans are or may be rated at 150 watts regardless of what lamps are used. How many 65 watt cans on a 15 amp circuit? How many 150 watt cans? Just like a receptacle uses 180va for calculation purposes.

klarson, no. You have to stay with the same size wire throughout the circuit. 15 amp for 14 wire and 20 amp for 12 wire. If you are running a new circuit just for the lights 14 is fine and will be much easier to work with in the cans.

 

You CANNOT use #14 on a 20amp. breaker. The max. amperage for #14 is 15amps. You mentioned using 12/2 on a 15a breaker, so if you like just use 14/2 and the same breaker.

 

Except in rare circumstances (and none apply here), you cannot use any 14-gauge wire on a 20-amp circuit.

Although it might be very wise to calculate lighting load based on the maximum fixture rating, I'm not aware of any code that requires you to do so on a residential circuit.

 

John,

220.3(B)(4)

 

Article 220 does not apply to nor restrict the design of an individual residential circuit. Article 220 is for computing the aggregate demand load on the service.

 

What about 220.3(C)(1)(2)?

 

Sorry Speedy, I'm 2000 miles away from my code book right now, so I can't look it up.

 

Hey John, no problem. I'm not questioning you. I'm just saying how I interpret it.
Basically 220.3(C)(1)(2) says to use 220.3(A) or (B) in cases of adding circuits to existing dwelling units. 220.3(B)(4) says to use the maximum va for calculating recessed lights.

 

MAN!! I wish I was 2000 miles from my code book!

 

The thread got a bit confusing with the rule citations.
Is the load based on maximum wattage blub allowed or anticipated blubs used in a fixture.

I bought some Halo H7ICT fixtures. I put 14 cans on a single dedicated 15A new circuit. The cans are in three different rooms
Living Room - 4, Den - 6, Basement -4.

The cans are only rated for 90Watts when using a BR40 Blub.
which would imply a load of 1260 watts if all blubs are switched on. which is a Tad over 1200 watts (80% load).

In convention I will be using Par 30, 65 watt blubs (910 watts if all switched on)

So which is the proper way for a homeowner to load the circuit
total wattage based on fixture maximum rating or actually load used.

 

It really depends on the circuit. Some recessed are calculated using the 3 watts per sq/ft. rule for general lighting. This is mainly for load calculations though.
For a new lighting circuit I would use actual wattage and use the maximum for the fixture.


15 amps x 120 volts= 1800 watts x 80%= 1440 watts continuous.

You are more than fine, even at 1260 watts.