104 design project: Cable design

[Aiden1]

Hi all, just a quick question for when designing a lighting circuit. I cant remember if you have to add up of all the wattages of the lights in the circuit or its just the same wattage from one light for the whole circuit?

 

[Typhoonut]

HI Aiden,

You’d need to include each light in the circuit in your calculation

 

[Aiden1]

HI Aiden,

You’d need to include each light in the circuit in your calculation

thank you

 

[pc1966]

As above, you have to assume that all lights could be on at once so add them up.

However, for voltage drop the usual assumption is they are distributed evenly along the cable's length so you get twice the acceptable length for a given %VD and total current. Of course if there is a very long feeder section, or the majority of loads are clustered in one place, that won't be quite true but unless the total wattage is significant it is unlikely to be a problem.