How many low voltage indoor lights ?

I am replacing some standard recessed lights with low voltage recessed lights. These are halogen low voltage and not CFBs. I am wondering if I can increase the number of lights on this leg of the circuit from the existing 6, would like 8 (there are other lights throughout the house on this 15A circuit). Today there are six 6inch 65W standard incandescent lights, would like 8 low voltage (12v) 50W lights. Not sure if there is anything specific I need to be concerned with with respect to low voltage lighting. thanks. Should of added, the potentially new lights have integrated transformers. It is not 1 transformer for all shared lights, 1 transformer (integrated to recessed can) per light. thanks.

Public Comments

1. as long as the total wattage of the lights does not exceed the power output of the transformer, you can add more. you will have to divide the number of light by wattage by the amount of output available, you cannot exceed that with burning out the transformer and perhaps causing a fire
2. Add up the total number of watts for all the light on the circuit & divide by 120 will give you the number of amps that you will use. On the package of new lights, there should be a minimum number of amps needed per light. Add this number to the total from above to see if it's possible.
3. 12V lights? I am assuming that there is a transformer that these lights plug into (or are wired into) somehow, and that transformer then,,, does it plug into an outlet or does it need to be hard-wired? Canned/recessed lighting is made for 110/120V AC voltage. When I hear 12V lighting, I'm thinking that it's really DC, converted and stepped down to 12 volts. Is this really the case? If so, then take the total amout of wattage that these lights are. Don't assume you can just add and add and add lights to that transformer because the wires that the transformer uses to power those lights are in all likelihood smaller than 12 or (for 15A ciruits) 14 gauge. Which means that their current rating is less, meaning you could overload the wires if you load enough lamps on a single transformer. Also, these transformers are labeled (usually) with their max current output, otherwise the lights will not brighten to full power, since they're all sapping the current. That transformer *is* limited, the upstream wires are not (w/ exception to the limit of the circuit breaker). NEC states that the breakers ought not to be loaded with more than 80% of anticipated load at full usage (with some exceptions, so check the book, and 2008 is a new issue). So taking the 65W previous lamps at 120V, 6 lamps were pulling 3 1/2 amps (Power=Current x Voltage). 50W divided by 12V means that each lamp pulls over 4 amps each, with eight lamps pulling over 30 amps of current. There are not 30 amps being pulled from your panel, there are 30 amps being pulled off of the transformer. Remember, the voltage is stepped down roughly 10x, which means that the current upstream of the transformer is 1/10, which brings us to around 3 amps. So make sure that the transformer wires can handle 30A DC or you'll have problems. I don't know what else is loaded on your circuit, so it's hard to say your limit is. But 80% of the circuit (breaker) rating is 12A, so make sure that you don't have 9A worth of things already on it otherwise you're maxxed out.