Repair,Meyer Electrical Services Inc.
Written by Walt Meyer

Electrical Subpanels for Apartments, Hotels & Motels – Part 2

Part 2 will discuss Electrical Subpanel Sizing, Wiring, and Costs.


As determined by its function and the power demands of a facility, subpanels will vary in electrical capacity. Houses typically need smaller subpanels ranging from 30 to 60 amps. On the other hand, commercial requirements will be greater, ranging from 60 to 100 amps. This is because apartment buildings, hotels, or motels often require heavier equipment, including elevators, commercial washers and dryers, and HVAC systems.  


A commercial electrical sub-panel requires that two hot wires be connected to a 240-volt double-pole breaker inside the main service panel. A ground wire and neutral wire will also be required. Described as a “three-wire cable with the ground,” this cable functions like feeder wires. Its two hot wires supply all the electricity to the sub panel.

The three-wire cable with the ground is connected to a 240-volt main breaker within the subpanel, supplying power to two hot bus bars. Connected to these bus bars, circuit breakers distribute current to branch circuits running from the sub-panel.

Commercial electrical subpanels are typically 3-phase panels manufactured for 3-pole, 2-pole, and 1-pole circuit breakers. In addition, most are rated for electrical services up to 600 volts. 3-phase commercial panels require three out-of-phase hot wires, resulting in greater efficiency due to the average power being higher than a single phase. Moreover, 3-phase panels provide steadier continuous power.


Commercial subpanels are more expensive than subpanels designed for residences. This is because they are made with more robust materials and require more wiring. Their load factors are more complicated, and they have more transformers. In addition, commercial electrical subpanels are designed to be highly efficient.

The cost of installing a commercial electrical sub panel will be less than upgrading the main service panel, also known as a heavy-up. This is because subpanels require less wiring. After all, they are smaller. Commercial subpanel installations range in cost from $1,000 to $2,500. The total cost will be determined by an electrical subpanel’s size, installation location, and its service area’s accessibility.

Electrical Services You Can Trust

Founded in 1991, Meyer Electrical Services provides home and commercial electrical services in Maryland, Virginia, and D.C., where we are licensed and insured. Based in Bethesda, our team proudly serves all of Montgomery County. Receive a free consultation for custom electrical work today by calling (301) 941-1400.