Residential or non-residential laundry?

[sfav8r]

We're bidding a job where we are wiring 3 washers and 3 gas dryers in the laundry area of a multi-unit building. What code section will cover this? Can I use the 75% rule for 4 or more appliances? There is currently only a subpanel with a 30a feed.

 

[LEO2854]

We're bidding a job where we are wiring 3 washers and 3 gas dryers in the laundry area of a multi-unit building. What code section will cover this? Can I use the 75% rule for 4 or more appliances? There is currently only a subpanel with a 30a feed.

210.52(F) see 210.11 (C)(2)

 

[sfav8r]

210.52(F) see 210.11 (C)(2)

OK, 210.52(f) states the minimum circuit required, but my question is what code section applies since this isn't a laundry room inside a residence. It is the common laundry area for multiple units. I plan to put each appliance on its own circuit, so that's not a problem. The question has to do with the load calculation for the feeder. I don't recall off the top of my head what the standard load is for a washer or a gas dryer, but lets just say it's 1,200 watts. I have 6 machines, which would be 7200 watts. The sub panel is only 120v so it would be 60 amps. (7200/60). Am I permitted to take 75% of the load due to the 6 appliances? Or does this not apply because it's nor treally in a residence?

 

[LEO2854]

OK, 210.52(f) states the minimum circuit required, but my question is what code section applies since this isn't a laundry room inside a residence. It is the common laundry area for multiple units. I plan to put each appliance on its own circuit, so that's not a problem. The question has to do with the load calculation for the feeder. I don't recall off the top of my head what the standard load is for a washer or a gas dryer, but lets just say it's 1,200 watts. I have 6 machines, which would be 7200 watts. The sub panel is only 120v so it would be 60 amps. (7200/60). Am I permitted to take 75% of the load due to the 6 appliances? Or does this not apply because it's nor treally in a residence?

In dwelling units Article 100 the Definitions a dwelling unit is defined. Your dryes are gas so that it is different than Electric gas dryers so 210 would apply not the load calculations in 220 about electric cls dryers.
I hope that helps:grin:

 

[lakee911]

We're bidding a job where we are wiring 3 washers and 3 gas dryers in the laundry area of a multi-unit building. What code section will cover this? Can I use the 75% rule for 4 or more appliances? There is currently only a subpanel with a 30a feed.

Deleted comment ... "gas" dryer. lol

Actually, does the code recognize a gas dryer as not needing as much capacity?

 

[Dennis Alwon]

I would consider a multifamily unit a dwelling and the laundry area as part of the dwelling even if it isn't inside each unit.

 

[hurk27]

OK, 210.52(f) states the minimum circuit required, but my question is what code section applies since this isn't a laundry room inside a residence. It is the common laundry area for multiple units. I plan to put each appliance on its own circuit, so that's not a problem. The question has to do with the load calculation for the feeder. I don't recall off the top of my head what the standard load is for a washer or a gas dryer, but lets just say it's 1,200 watts. I have 6 machines, which would be 7200 watts. The sub panel is only 120v so it would be 60 amps. (7200/60). Am I permitted to take 75% of the load due to the 6 appliances? Or does this not apply because it's nor treally in a residence?

Laundry circuits are calculated as 1500 va, for 3 washers and dryers would be 4500 va not 7200, each laundry circuit would be able to handle both a washer and a gas dryer.

4500 va would be 18.75 amps @ 240, so a 30 amp feeder would not be a problem.


Edited: Just saw that the sub panel is only 120 volts, so yes need more power, can it be refed with 240/120?

 

[hurk27]

to caculate a feeder load see 215.2 and 220.52(B)

for a 120 volt feeder you would need a feeder of at least 46.87 amps, which would require a 50 amp circuit.

 

[iwire]

The common laundry room is not a dwelling unit and the equipment in their cannot be calculated like it is one.

 

[jetlag]

I would not do any derateing on the washers even if code allowed since only 3 washers in a multi unit , there will probably be people in line often on weekends . I didnt think a gas dryer used enough current to worry about , the motor is small. maybe 3 amp each.

 

[sfav8r]

Thanks for all the input.

 

[Dennis Alwon]

The common laundry room is not a dwelling unit and the equipment in their cannot be calculated like it is one.

I would have to agree with Bob, even though it hurts me so.

210.25 Branch Circuits in Buildings with More Than One Occupancy.
(A) Dwelling Unit Branch Circuits. Branch circuits in each dwelling unit shall supply only loads within that dwelling unit or loads associated only with that dwelling unit.
(B) Common Area Branch Circuits. Branch circuits required for the purpose of lighting, central alarm, signal, communications, or other needs for public or common areas of a two-family dwelling, a multifamily dwelling, or a multi-occupancy building shall not be supplied from equipment that supplies an individual dwelling unit or tenant space.

I wonder if the multifamily was supplied by one meter would you still need a common area that is separate. Seems the code says yes but it doesn't make sense to enforce that unless the code is a design issue.