80% rule residential?

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mbrooke

mbrooke

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Does the 80% rule every apply to residential?

Large basement game room with 25 high hats. Total load comes to around 1650-1700 watts. Since code mentions nowhere that residential lighting shall be continuous does that mean I can load the circuit to the max?
 
mbrooke said:
Does the 80% rule every apply to residential?

Large basement game room with 25 high hats. Total load comes to around 1650-1700 watts. Since code mentions nowhere that residential lighting shall be continuous does that mean I can load the circuit to the max?
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Umm. No. You would need a 20A circuit to put all those lights on as they're loaded now, but you need to see what the max wattage is that the fixtures are rated for and base your calculation on that. If they're six inch cans that can take 150W PAR 38s, who's to say that someone isn't going to put those in five or ten years down the road?
 
PetrosA said:
Umm. No. You would need a 20A circuit to put all those lights on as they're loaded now,
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And what NEC section will you cite as the reason for that?

There is no hard and fast rule here, it is a judgment call if this load is continuous or not.
 
The 125% rule applies to a continuous load. It does not matter if it is residential, commercial, bank......
 
iwire said:
For sure.

Now, who or what determines it is a continuous load?
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I would simply ask the customer if they intend to use the lighting (OP case) for longer than 3 hrs. If they don't know the answer then it is better to do an educated guess and design the circuit accordingly.
 
NEC does specify some items must be considered a continuous load. Browse around especially in art 422 to 490 and you will find some of them.

Otherwise intended use is next best thing. Many will consider any general purpose lighting to be a continuous load, it is generally capable of running 3 hours or more.
 
mbrooke said:
2 3 way switches. The clacs were done based on the maximum wattage the high hats are allowed as per label. 65 watts max is the label.
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Since they're all on one switch than IMO it's a continuous load because they can be on at maximum ampacity for three or more hours. My wife leaves the basement lights on for days at a time. :roll:
 
So in theory its up to the person. As for commercial lighting, is it the same way. I hear commercial lighting is always continuous... is that required such as electric heat or just based on anticipation?
 
mbrooke said:
Ok. So no specific code section asks for it like water storage tanks?
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Just water storage tanks is too general, and doesn't usually have electrical energy applied to the tank itself, a pump or a heater or other application of power to some other specific component of the tank however....

One example in the water storage tank line of thinking is storage type water heaters. See 422.13 - it says these shall be considered as a continuous load.

There are other specific items mentioned here and there thougout 422 to 490 and maybe even an item or two elsewhere that says it shall be considered a continuous load
 
iwire said:
And what NEC section will you cite as the reason for that?

There is no hard and fast rule here, it is a judgment call if this load is continuous or not.
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Obviously the NEC doesn't declare residential lighting loads to be continuous but I think it would indicate neglect on the part of the electrician installing any lighting load over 80% of the circuit's capacity to consider it a non-continuous load, especially since lighting loads are one of the few loads we connect that don't cycle in any way. If you take that tack, where do you stop? Do you install 1800 watts of lighting in various rooms on one 15A circuit and claim that the fact that they're different rooms means that they'll never all be on at the same time?

mjf said:
OR.....sell LED's and reduce the wattage and don't worry about it!!:angel:
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Carefully, though. You still need to find out the max wattage allowed in a luminaire before you can figure out how many can go on one circuit. Even if you retrofit edison base LEDs in the fixtures, you still have to calculate for whatever max is allowed.
 
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Which is part of the reason that energy codes do not accept CFL or LED Edison base screw-ins, instead requiring special sockets.
Which works to your advantage in sizing the circuit.
 
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