Load calculation laundry room

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sparks27

Member
Location
Portland, Oregon
So I am trying to figure the optional calculation for a service feeding a laundryroom in a
apartment complex. this service has no other loads.
trying to figure how much load can be added to this existing service, We will be adding a subpanel later
for some Electric Vehicle charging.
I used the nameplate ratings on the equipment : Art. 220.82 (b)
service is 200a 120/240 1ph.

1.water heater 80 gal x 1 5616 watts 5616
2. washer machine x 6 7.0a ea. x 120v 5040
3 dryers x 6 5900 watts ea. 35400
4.carport lts. total 5880 watts 5880
5.room lts. 500 watts 500
6. gen recpts. x2 1500 watts ea. 3000

total 55,436 VA

first 10,000va @ 100% 10,000
remainder of 45,436 @ 40@ 18,174.40
total 28,174.40 VA / 240V

117.39 Amps
Am I on the right track here? Thanks, sparks
 

Smart $

Esteemed Member
Location
Ohio
Being an apartment complex, the building is classified as a multifamily dwelling. As such, this service appears to be house load only. It is ineligible for the optional calculation. See 220.84(B).
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
Being an apartment complex, the building is classified as a multifamily dwelling. As such, this service appears to be house load only. It is ineligible for the optional calculation. See 220.84(B).

I took House Loads to mean the loads for the common areas supplied by the HOUSE-- I would not call an apt a house. I never thought of it as you do and IMO it makes no sense to not allow each apt the use of the optional method
 

Smart $

Esteemed Member
Location
Ohio
I took House Loads to mean the loads for the common areas supplied by the HOUSE-- I would not call an apt a house. I never thought of it as you do and IMO it makes no sense to not allow each apt the use of the optional method
The apartments (dwelling units) are eligible. Common areas (House loads) are not.

OP says service supplies laundry room only... though his calculations also indicate it supplies car port lighting. With multiple washers and dryers, I have to assume this is a common area.
 

cadpoint

Senior Member
Location
Durham, NC
#3

Step 4: Household Dryer Calculated Load [220.54]

Dryers are allowed the demand factors of Table 220.54, but this table does not allow less than 100% demand until there are five units or more. The 5kW minimum per dryer applies to all dwelling units [220.54]. A laundry circuit isn't required for an individual dwelling unit if the multifamily unit has common laundry facilities.

IE #3 seems high...

ECM
 

sparks27

Member
Location
Portland, Oregon
#3

Step 4: Household Dryer Calculated Load [220.54]

Dryers are allowed the demand factors of Table 220.54, but this table does not allow less than 100% demand until there are five units or more. The 5kW minimum per dryer applies to all dwelling units [220.54]. A laundry circuit isn't required for an individual dwelling unit if the multifamily unit has common laundry facilities.

IE #3 seems high...

ECM

I used the nameplate rating on the dryer and it says 5900 w. the table 220.54 says 5000w to be used
so that's a reduction there.
220.84 (B) says, I have to use part III to calculate house loads.
 

sparks27

Member
Location
Portland, Oregon
I used the nameplate rating on the dryer and it says 5900 w. the table 220.54 says 5000w to be used
so that's a reduction there.
220.84 (B) says, I have to use part III to calculate house loads.

this laundry has 6 dryers
six washer mach.
very little lighting: inside laundry 4- 2ft flour strip lts.
there are 7-lighting cirs. on a contactor.
about 7 amps ea.
two gen use plug cirs 1500 ea.
and a 80 gal. wtr. htr. nameplate 23.4 A (hybrid)

I will use part III to calculate then.
 

cadpoint

Senior Member
Location
Durham, NC
Maybe I'm wrong why did you by-pass 220.84(A), this is where the Table 220.84 is called out.

Now in the OP you didn't exactly state that this was a multiply unit dwelling or a duplex or exactly what it was.
 

sparks27

Member
Location
Portland, Oregon
Maybe I'm wrong why did you by-pass 220.84(A), this is where the Table 220.84 is called out.

Now in the OP you didn't exactly state that this was a multiply unit dwelling or a duplex or exactly what it was.

I didn't know that the laundry room had to use the multifamily dwelling calculation. 220.84

The service for this Laundry room has its own separate service, no apartment loads in it.

It is a multifamily dwelling 12 apts. per bldg.

My oversight there there.
 

sparks27

Member
Location
Portland, Oregon
That is exactly what makes it a house load, not paid for directly by any tenant.

okay, so now I have the 220.84 calculation table. following that , it says to add up the loads
220.84 (C) and apply the demand factor to the following, sections 1-5.

dryer nameplate rating 5900va x6 = 35,400va
washer cir 1500va x 6 = 9000va
water heater name rating 5616 va = 5616 23.4 A/240
laundryroom 200 sq. ft.x 3va 600va
walk lites x 7.0a x 6 cirs. 5880va how else to rate these?
total 50,616 va

apply table 220.84 12 apts. 41% 20,752.5

divide by 240V = 86.46 amps

So I am on the Right track here?
thanks for the replies, Sparks
 

sparks27

Member
Location
Portland, Oregon
That is exactly what makes it a house load, not paid for directly by any tenant.

okay, so now I have the 220.84 calculation table. following that , it says to add up the loads
220.84 (C) and apply the demand factor to the following, sections 1-5.

dryer nameplate rating 5900va x6 = 35,400va
washer cir 1500va x 6 = 9000va
water heater name rating 5616 va = 5616 23.4 A/240
laundryroom 200 sq. ft.x 3va 600va
walk lites x 7.0a x 6 cirs. 5880va how else to rate these?
total 50,616 va

apply table 220.84 12 apts. 41% 20,752.5

divide by 240V = 86.46 amps

So I am on the Right track here?
thanks for the replies, Sparks
 

Smart $

Esteemed Member
Location
Ohio
okay, so now I have the 220.84 calculation table. following that , it says to add up the loads
220.84 (C) and apply the demand factor to the following, sections 1-5.

dryer nameplate rating 5900va x6 = 35,400va
washer cir 1500va x 6 = 9000va
water heater name rating 5616 va = 5616 23.4 A/240
laundryroom 200 sq. ft.x 3va 600va
walk lites x 7.0a x 6 cirs. 5880va how else to rate these?
total 50,616 va

apply table 220.84 12 apts. 41% 20,752.5

divide by 240V = 86.46 amps

So I am on the Right track here?
thanks for the replies, Sparks
You seem to be stuck. :happyyes:

Being an apartment complex, the building is classified as a multifamily dwelling. As such, this service appears to be house load only. It is ineligible for the optional calculation. See 220.84(B).
 

sfork2020

Member
Location
Quogue N Y
Occupation
Electrician
So if this was a commercial laundromat all the nameplate rating’s would be added up at 100% you then take the total VA and multiplied by 1.732 for three phase. Lighting would also be considered at 100% due to it being on for three hours or more?? Would that be correct ?
 
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