Calculating Load

[onemarketplace]

I have a question regarding load calculation. Let 's say I have one 150W 120/12V transformer that feed (4) 35 Wats lamps. My question is;

Do I take the load from the (4) 35W fixtures or just take it from the transformer (150W/12V=12.5A). Because at the end, the loads added by the lights are less than what the transformer can offer.


Thanks

 

[iwire]

Are you looking for the service load or the branch circuit?

 

[onemarketplace]

Are you looking for the service load or the branch circuit?

I am looking for branch circuits. Thanks

 

[iwire]

I guess it really does not matter as 220.14(D) 2008 seems to apply to both and requires the the calculation use the max VA the equipment is rated for.

 

[onemarketplace]

I guess it really does not matter as 220.14(D) 2008 seems to apply to both and requires the the calculation use the max VA the equipment is rated for.

Thanks for your help.


Is it the same with fluorescent fixtures. Do you use the ballast rating instead of the total lamps installed?

Thanks Again

 

[iwire]

Thanks for your help.


Is it the same with fluorescent fixtures. Do you use the ballast rating instead of the total lamps installed?

No problem and yes. :smile:

 

[LarryFine]

I have a question regarding load calculation. Let 's say I have one 150W 120/12V transformer that feed (4) 35 Wats lamps. My question is;

Do I take the load from the (4) 35W fixtures or just take it from the transformer (150W/12V=12.5A). Because at the end, the loads added by the lights are less than what the transformer can offer.

You do realize that, in this case, you're comparing 140w and 150w, or 11-2/3a vs 12.5a. Not a huge difference. And it never hurts to allow a bit of headroom.