How many subpanels can you install to one another? This Chief Electrical Inspector has the answer.
Question: Can a subpanel have power supplied from a circuit breaker into another subpanel? In other words, can you daisy-chain subpanels?
The main electrical service panel is where branch circuits originate. A branch circuit consists of the circuit conductors between the final over-current device protecting the circuit and the lights, receptacles and equipment supplied by the branch circuit.
There are three main types of branch circuits:
- General-purpose branch circuits for illumination and other general purposes
- Appliance branch circuits that supply power in the kitchen for countertop receptacles, such as small appliances
- Individual branch circuits that only supply one utilization equipment, such as a central heating gas furnace, an electric clothes dryer, an electric range and so on.
The main service panel also may contain fuses or circuit breakers that supply “feeder” conductors to downstream subpanels. A feeder consists of the circuit conductors that originate at the main service panel and are routed to the subpanel, in which there are branch circuit over-current devices for the downstream branch circuits.
You could daisy-chain a feeder from the main service panel (Panel A) to a subpanel (Panel B), and then run another feeder from Panel B to another subpanel (Panel C). There really is no limitation to this concept, as long as every set of feeder and branch circuit conductors are properly sized and rated in amperes, and each feeder and branch circuit has the proper over-current protection (fuse or circuit breaker).
Always check with your local electrical inspector about the specific code requirements in your area.
Question answered by John Williamson, Chief Electrical Inspector, Minnesota Department of Labor and Industry
John Williamson has been in the electrical industry for 40 years and is a licensed master electrician and certified building official. John has worked for the state of Minnesota for over 23 years and is the Chief Electrical Inspector. For the past 25 years John has also provided electrical code consultation to various book and magazine publishers