Young electrician

[joeyww12000]

On a recent job the lights we installed were fed through relays instead of just coming off load side of the breaker. Stupid question, but why do we use relays? Is this just more convenient than flipping a breaker to control lighting?

 

[jrannis]

Usually its a way to control many lights on several circuits with one just switch or lighting management control system

 

[broadgage]

Another reason is to reduce voltage drop if lighting control from a distant point was required.
The wires may be run from the load center, via a relay, to the lights by the shortest/most direct suitable route.
The wires controlling the relay coil can be of almost unlimited length since they carry only a small current.

 

[kjfelec]

Easier control of lights.

Don't be afraid to ask questions on the job or anywhere else. It is the best way to learn and understand what is going on. If you dont understand, ASK.

Kelley

 

[charlie b]

Another reason is to permit remote, automated control. For example, all lights might be programmed to turn off at a given time of night, and to be turned on again at a given time in the morning, with local override switches available for those who might be working late.

 

[K8MHZ]

A third reason would be so that all the lights don't come on all at once, reducing in rush current. You will see this in large department stores and large open office spaces.

 

[pbeasley]

Out here in California this has been discussed on a number of projects for load shedding purposes. I have not seen any actually get built yet.

 

[kingpb]

It could be a way of having a bunch of lights on one circuit, but maintaining ability to control various lights for different reasons.

A combination of some of the other replies.