Multi-Outlet Assembly Load Calculator
Calculate the feeder or service load of a fixed multioutlet assembly (surface raceway with receptacles) in a commercial occupancy. Enter the run length; the tool applies the NEC 220.14(H) length rule - 180 VA per 5 ft where appliances are unlikely to run at once, or per 1 ft where they are likely to - and reports the connected volt-amperes and amperes.
How to use this calculator
- Enter the length of one continuous assembly run in feet, and how many identical runs there are. Runs of different lengths are computed separately and added.
- Choose the appliance use: unlikely simultaneous applies 180 VA per 5 ft (NEC 220.14(H)(1)); likely simultaneous applies 180 VA per 1 ft (220.14(H)(2)).
- Pick the voltage and phase of the feeder or panel for the demand-current readout.
- Read the connected load in volt-amperes and its amperes. The tool shows the 180 VA rate, the outlets per run, and the total outlet count, and notes where the Table 220.44 demand factors may be applied.
NEC reference
This calculator follows the National Electrical Code (NEC) 2020. Section 220.14(H)(1) counts each 5 ft, or fraction thereof, of a fixed multioutlet assembly as one outlet of not less than 180 volt-amperes where the appliances are unlikely to be used simultaneously; Section 220.14(H)(2) counts each 1 ft, or fraction thereof, as one 180 VA outlet where they are likely to be used simultaneously. These provisions apply to other-than-dwelling occupancies and are unchanged across the 2017, 2020, and 2023 editions, so no edition toggle is offered.
Results are for reference only. Verify against the applicable adopted edition of the NEC and consult a licensed electrician for code compliance.
The two NEC 220.14(H) rates
A fixed multioutlet assembly is counted by length rather than by the number of receptacles on it. The rate depends on how likely the connected appliances are to draw at once, and each partial segment counts as a full 180 VA outlet.
| NEC section | Appliance use | Load |
|---|---|---|
| 220.14(H)(1) | Unlikely simultaneous | 180 VA per 5 ft |
| 220.14(H)(2) | Likely simultaneous | 180 VA per 1 ft |
Values are NEC 2020 220.14(H). Each 5 ft or 1 ft "or fraction thereof" is one 180 VA outlet, so a partial segment rounds up.
Worked example: 40 ft of assembly
A commercial space has a 40 ft run of fixed multioutlet assembly. Where the appliances are unlikely to be used at the same time, 40 / 5 = 8 outlets at 180 VA each is a connected load of 8 x 180 = 1,440 VA. Where they are likely to be used at the same time, 40 / 1 = 40 outlets x 180 = 7,200 VA. On a 208 V, 3-phase feeder the 1,440 VA figure is 1,440 / (208 x 1.732) = 4.0 A. This matches the widely published EC&M and Mike Holt Article 220 multioutlet-assembly example.
Several runs and "or fraction thereof"
The "or fraction thereof" rounding applies to each continuous run, not to a combined total. Three separate 4 ft runs in the non-simultaneous case are each 4 / 5 rounded up to one 180 VA outlet, for 3 x 180 = 540 VA, whereas one continuous 12 ft run is 12 / 5 = 2.4 rounded up to 3 outlets = 540 VA and a single 4 ft run is one outlet = 180 VA. Enter the length of one run and the number of identical runs; compute runs of different lengths separately and add them.
The Table 220.44 demand-factor option
NEC 220.44 permits, but does not require, the multioutlet assembly load to be added to the other receptacle loads and taken at the Table 220.44 demand factors - the first 10 kVA at 100% and the remainder at 50%. This tool reports the 100% connected load, the conservative never-undersize figure. When that demand reduction is taken, combine this assembly load with the general-use receptacle load in the Commercial Receptacle Load Calculator, which applies the Table 220.44 factors across the combined receptacle total.
What this tool does not do
- Ordinary receptacle straps (NEC 220.14(I)). A single or multiple receptacle on one strap is 180 VA per yoke, a separate rule from the length-based assembly load. Use the Commercial Receptacle Load Calculator.
- The Table 220.44 demand reduction. The assembly load is reported at 100%; apply the demand factors across the combined receptacle load where 220.44 permits it.
- Dwelling-unit occupancies. 220.14(H) is a non-dwelling rule; dwelling receptacles are in the general lighting VA/ft² load (220.14(J)).
- Conductor, overcurrent device, and neutral sizing. Size those with the Wire Size, Breaker Size, and Neutral Load calculators (NEC 210.19, 240.4, Table 310.16, 220.61).
Frequently asked questions
Is plugmold a fixed multioutlet assembly?
Yes. A fixed multioutlet assembly is a surface metal or nonmetallic raceway with receptacles spaced along it; plugmold is a common trade name for one. Its feeder and service load is calculated by the 220.14(H) length rule, not by counting each receptacle at 180 VA.
Does the assembly load get the 125% continuous multiplier?
Not as part of the 220.14(H) calculation. The 180 VA per length figure is the calculated load. If a specific assembly serves a known continuous load, that continuous load is sized at 125% for its conductor and overcurrent device under 210.19 and 210.20, outside this general-assembly method.
Is this the same as the whole-building commercial load calculation?
No. This computes only the multioutlet-assembly line. A full commercial service calculation adds general lighting, general-use receptacles, kitchen equipment, show-window and sign loads, and more. Use the Commercial Load Calculator for the complete service size.
Related calculators
- Commercial Receptacle Load Calculator: the per-strap 220.14(I) receptacle load and the Table 220.44 demand factors for the combined receptacle total.
- Commercial Load Calculator: the full NEC 220 Part III non-dwelling service calculation.
- Show Window & Sign Lighting Load Calculator: the 200 VA per foot show-window load and the 1200 VA per sign circuit.
- Wire Size Calculator: the feeder conductor for the assembly load, for ampacity and voltage drop.
Studying for the licensing exam? Our own NEC Code Quickstart works all twelve exam calculations start to finish, each with the code reference. Also in paperback.
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