In Article " NonDwelling Buildings Load Calculations Part One ", I introduced a List for ordinary NonDwelling Buildings Loads which was as follows:
 Lighting loads,
 Receptacles Loads,
 Kitchen Loads,
 Heating, Ventilation and air conditioning Loads (NonCoincident Loads),
 Motor Loads,
 Other Loads.
Again, but for above NonDwelling Buildings Loads, I will explain the following points:
 Where and how to distribute each type of load in a dwelling unit as per NEC code?
 How to calculate its Demand load for feeder and service sizing calculations?
Important!!!
All design Calculations for Nondwelling Buildings will be as per
NEC standard calculation method but I will explain design calculations as per
NEC Optional calculation method only for the following NonDwelling buildings
as permitted by NEC, Part IV. Optional Feeder and Service Load Calculations:

I explained the Design Calculation for first type of NonDwelling Building loads which is Lighting loads in Article " NonDwelling Buildings Load Calculations Part One ".
Also, I explained parts one & Two of Design Calculation for second type; Receptacle loads for NonDwelling Buildings in Articles:
Today, I will explain the Design Calculation of Receptacle loads  Third part for NonDwelling Building Loads which is Receptacle Loads.
Second: Receptacle Loads – Part Three
1 General –Use Receptacle Loads in NonDwelling Units
Important!!!
The receptacle outlets in NonDwelling
Buildings will be counted to calculate their load, unlike the Dwelling
buildings where the GeneralUse Receptacles Load is calculated with the
general lighting Load by multiplying Building Area in (ft2) with its power
density in (VA/ft2) from table 220.42 in below image.

Important!!!
GeneralUse Receptacles are notcontinuous
Loads, No need to multiply it by 1.25 to calculate their contribution in the
total load.
But, if a Receptacle is
dedicated for a specific device, then the actual load is used and If this
dedicated load is continuous, then the 125% overrate is appropriate.

Rule#1: GeneralUse
Receptacle Load (see below image)
As per NEC section
220.14(I), Receptacle outlets load shall be calculated at not less than:

Important!!!
The general lighting load
unit values specified in table 220.42 for guest rooms or guest
suites of hotels and motels includes All generaluse receptacle
outlets of 20ampere rating or less, including receptacles connected to
Bathroom Branch Circuits,
So, no need to add the above
outlets in load calculations per NEC method.

Example#1:
For a commercial building having 75 duplex and 10 single receptacles, what is the calculated load for these receptacles?
Solution:
As per NEC section 220.14(I), Receptacle outlets load shall be calculated at not less than:
180 voltamperes for each single receptacle, 180 voltamperes for each multiple receptacle (duplex or triplex) on one yoke/strap.
So, Receptacle calculated load = (75+10) x 180 VA = 15,300 VA
Important!!!
In Commercial and Industrial
Buildings, it is common to use fixed
multioutlet assemblies, which can be classified to two types according to
method of usage as follows:

Rule#2: Fixed
Multioutlet Assemblies Load (see below image)
As per NEC section
220.14(H), Fixed multioutlet assemblies used shall be calculated as follows:

Important!!!
Fixed multioutlet assemblies are notcontinuous
Loads, No need to multiply it by 1.25 to calculate their contribution in the
total load.
But, if Fixed multioutlet
assemblies is dedicated for a specific device, then
the actual load is used and If this dedicated load is continuous, then the
125% overrate is appropriate.

Important!!!
Fixed multioutlet assemblies
in guest rooms or guest suites of hotels and motels are included in The
general lighting load unit values specified in table 220.12.
So, no need to add the Fixed
multioutlet assemblies in load calculations for these locations.

Example#2:
For a commercial building has 75 linear feet of fixed multioutlet assembly, with 15 feet of the assembly subject to simultaneous use. What is the calculated load for this fixed multioutlet assembly?
Solution:
Length of fixed multioutlet assembly Portion for Non simultaneous use (Light Use) = 75 – 15 = 60 linear feet.
Calculated load for Light use portion = (60/5) x 180 VA = 2,160 VA Calculated load for Heavy use (simultaneous use) portion = 15 x 180 VA = 2,700 VA
Total calculated load for this fixed multioutlet assembly = 2,160 VA + 2,700 VA = 4,860 VA
Rule#3: GeneralUse
Receptacles and Fixed Multioutlet Assemblies Loads Demand Factors
As per NEC section
220.44, GeneralUse Receptacles and Fixed Multioutlet Assemblies are subjected to demand factors by either
of the following two methods:

Example#3:
The general lighting load, before applying demand factors, for hospital patient rooms is 100,000 voltamperes. The receptacle branchcircuit load, calculated in accordance with 220.14(H) and (I), is 144,000 voltamperes. What is the lighting and receptacle load after demand factors?
Solution:
Since Hospital is one of the building types (other than dwelling units) listed in Table 220.42, the receptacle load could be added to the general lighting load and made subject to the demand factors in Table 220.42.
Total load = lighting load + receptacles load = 100,000 VA+ 144,000 VA = 244,000 VA
Then apply demand factors for hospital from table 220.42 as follows:
Multiply the first 50,000 by 40 percent = 50,000 × 40% = 20,000 VA
The Remaining = 244,000 – 50,000 = 194,000 VA
Multiply the remaining by 20 percent = 194,000 × 20% = 38,800 VA
The lighting and receptacle load, after applying Table 220.42 demand factors= 20,000 + 38,800 = 58,800 VA
Example#4:
For a hospital building, the receptacle branchcircuit load is 144,000 voltamperes. What is the receptacle load after applying the demand factors in Table 220.44?
Solution:
Applying the demand factors in Table 220.44
The first 10 kVA is multiplied by 100 percent = 10,000 x 100% = 10.000 VA
The remainder = 144,000 – 10,000 = 134,000 VA
Multiply the remainder by 50 percent = 134,000 × 50% = 67,000 VA
Then, the receptacle load, after applying Table 220.44 demand factors = 10,000 + 67,000 = 77,000 VA
Example#5:
A store has a total of 80 duplex receptacles. What is the receptacle load after demand factors?
Solution:
First, multiply the 80 receptacles by 180 voltamperes.
Receptacle load before applying demand factors = 80 × 180 VA= 14,400 VA
Second, Applying the demand factors in Table 220.44
The first 10 kVA is multiplied by 100 percent = 10,000 x 100% = 10.000 VA
The remainder =14,400 – 10,000 = 4,400 VA
Multiply the remainder by 50 percent = 4,400 × 50% = 2,200 VA
Then, the receptacle load, after applying Table 220.44 demand factors= 10,000 + 2200 = 12,200 VA
Rule#4:
Special case#1:
where the actual number of receptacle outlets in banks and office buildings
is unkown
As per NEC section
220.14(K), in bank and office buildings, if the number of receptacles is
unknown, we can calculate the receptacles load by multiplying the bank or
office building area in ft2 by the unit value (1 VA/ft2).

Rule#5:
Special case#2:
where the actual number of receptacle outlets in banks and office buildings
is kown
As
per NEC section 220.14(K), in bank and office buildings, if the number of receptacles is known, then we can
calculate the receptacles load to be the larger of the following two loads:

Example#6:
In an 8,500 square foot bank, it is not known how many receptacles are there, what is the calculated load for receptacles?
Solution:
As per NEC section 220.14(K), in bank and office buildings, if the number of receptacles is unknown, we can calculate the receptacles load by multiplying the bank or office building area in ft2 by the unit value (1 VA/ft2).
The calculated load for receptacles = 8500 ft2 x 1 VA/ft2 = 8,500 VA
In the next article, I will continue explaining load calculations for other types of loads in NonDwelling Buildings. Please, keep following.
Post a Comment
Leave a comment to help all for better understanding