Indiana Administrative Code
Title 675 - FIRE PREVENTION AND BUILDING SAFETY COMMISSION
Article 15 - INDUSTRIALIZED BUILDING SYSTEMS
Rule 2 - Indiana Mobile Structures Code
Section 2-100 - Load calculations

Universal Citation: 675 IN Admin Code 2-100

Current through September 18, 2024

Authority: IC 22-13-2-13

Affected: IC 22-12; IC 22-13; IC 22-14; IC 22-15

Sec. 100.

(a) The following method shall be employed in computing the supply cord and distribution panelboard load for each feeder assembly for each mobile structure and shall be based on a three (3) wire, one hundred fifteen/two hundred thirty (115/230) volt supply with one hundred fifteen (115) volt loads balanced between the two (2) legs of the three (3) wire system.

(1)) Method No. 1; Lighting and Small Appliance Load. Lighting Watts: Length times width of mobile structure (outside dimensions, exclusive of coupler) times three (3) watts per square foot; e.g., Length × Width × 3 = _____ lighting watts. Small Appliance Watts: Number of circuits times one thousand five hundred (1500) volt amperes for each twenty (20) ampere appliance receptacle circuit (see definition of "appliance, small" with note); e.g., Number of circuits × 1500 = _____ small appliance volt-amperes.

Total lighting watts plus small appliance = _____ total volt-amperes.

First three thousand (3000) total volt-amperes at one hundred percent (100) plus remainder at thirty-five percent

(35%) = _____ volt-amperes to be divided by two hundred thirty (230) volts to obtain current (amperes) per leg.

Total load for determining power supply is the summation of:

(A) Lighting and small appliance load is calculated in (a)(1).

(B) Nameplate amperes for motors and heater loads (exhaust fans*, air conditioners*, electric gas, or oil heating.+)

*Omit smaller of these two (2), except include blower motor if used as air-conditioner evaporator motor.

+When an air conditioner is not installed and a forty (40) ampere power supply cord is provided, allow fifteen (15) amperes per leg for air conditioning.

(C) Twenty-five percent (25%) of current of largest motor in item (B) above.

(D) Total of nameplate amperes for: disposal, dishwasher, water heater, clothes dryer, wall-mounted oven, cooking units.

Where number of these appliances exceed three (3), use seventy-five percent (75%) of total.

(E) Derive amperes for free-standing range (as distinguished from separate ovens and cooking units) by dividing values below by two hundred thirty (230) volts.

Nameplate Rating Use
10,000 w × or less 80% of rating
10,001 - 12,500 w 8,000 v-a
12,501 - 13,500 w 8,400 v-a
13,501 - 14,500 w 8,800 v-a
14,501 - 15,500 w 9,200 v-a
15,501 - 16,500 w 9,600 v-a
16,501 - 17,500 w 10,000 v-a

(F) If outlets or circuits are provided for other than factory-installed appliances include the anticipated load.

NOTE: The following example is given to illustrate the application of this Method of Calculation:

EXAMPLE A mobile structure is 70 x 10 feet and has two (2) portable appliance circuits, a 1000 watt 230 volt heater, a 200 watt 115 volt exhaust fan, a 400 watt 115 volt dishwasher and a 7000 watt electric range. Lighting and small appliance load.

Lighting 70 × 10 × 3 = 2100 v-a
Small appliance 1500 × 2 = 3000 v-a
Laundry 1500 × 1 = 1500 v-a
6600 v-a
1st 3000 at 100%...................... ........... 3000
Remainder (5100 - 3000 = 2000) @ 35%... ........... 1260
4260
4260 = 185 amperes per leg 230
1000 watt (heater) divided by 230 = 4.4 amp
200 watt (fan) divided by 115 = 1.7 amp
400 watt (dishwasher) divided by 115 = 3.5 amp
7000 watt (range) ×.8 divided by 230 = 24.0 amp

Amperes Per Leg
A B
Lighting and appliances 18.5 18.5
Heater (230 volt) 4 4
Fan (115 volt) 2 -
Dishwasher (115 volt) - 4
Range 24 24
Totals 48.5 50.5

Based on the higher current calculated for either leg, use one (1) fifty (50) ampere supply cord.

(2) Method No. 2; Optional Method of Calculation for Lighting and Appliance Loads. For mobile structures served by a single three (3) wire one hundred fifteen/two hundred thirty (115/230) volt set of feeder conductors with an ampacity of one hundred (100) or greater, the total load for determining the feeder ampacity may be computed in accordance with Table 100(a)(2) instead of the methods specified in (a)(1). Feeder conductors whose demand load is determined by this optional calculation shall be permitted to have the neutral load determined by section 220-22 of the Indiana Electrical Code (675 IAC 17-1 [675 IAC 17-1 was repealed filed Feb 17, 1987, 3:15 p.m.: 10 IR 1389, eff Mar 1, 1987 [ IC 4-22-2-36 suspends the effectiveness of a rule document for thirty (30) days after filing with the secretary of state. LSA Document #86-153 was filed Feb 17, 1987.].]). The loads identified in Table 6B, below as "other load" and as "remainder of other load" shall include the following:
(A) One thousand five hundred (1500) watts for each two (2) wire, twenty (20) ampere small appliance branch circuit and each laundry branch circuit specified.

(B) Three (3) watts per square foot for general lighting and general-use receptacles.

(C) The nameplate rating of all fixed appliances, ranges, wall-mounted ovens, counter-mounted cooking units, and including four (4) or more separately controlled space heating units.

(D) The nameplate ampere of kVA rating of all motors and all low-power factor loads.

(E) The largest of the following:
(i) air-conditioning load;

(ii) the sixty-five percent (65%) diversified demand of the central electric space heating load;

(iii) the sixty-five percent (65%) diviersified [sic.] demand of the load of less than four (4) separately-controlled electric space heating units; (iv) the connected load of four (4) or more separately controlled electric space heating units.

TABLE 6B Optional Calculation for Mobile Structures with 100-Amperes or Larger Service

Load (in kW or kVA) Demand Factor (Percent)
Air-conditioning and cooling, including heat pump compressors........ . 100
Central electric space heating ................................... . 65
Less than four (4) separately controlled electric space heating units...... . 65
First ten (10) kW of all other load ................................ . 100
Remainder of other load ....................................... . 40

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