What is the difference between main panel and sub panel?

Asked By: Geneva Juhno | Last Updated: 20th March, 2020
Category: home and garden indoor environmental quality
4.6/5 (185 Views . 13 Votes)
The biggest difference between a subpanel and a main panel is that the ground and neutral buses on a subpanel have to be separated. Most panels come with a bar joining the two, which is easily removed. Code requires subpanels to have a ground connection that's independent of the main panel's.

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Herein, can I use a main panel as a sub panel?

Can You Use a Main Breaker Panel As the Subpanel? A standard 100-amp load center can be used as a subpanel, according to electrical-online.com. The neutral bonding jumper, however, must be removed. In a subpanel, the neutral must be completely isolated from the ground.

One may also ask, how do you hook up a sub panel to a main panel? If the panel is full, you may have to shift one of the 240-volt circuits or two 120-volt circuits to the subpanel to make room. Connect the neutral wire to the neutral bus and the ground wire to the ground bus, turn on the main breaker and the subpanel breaker and the subpanel is energized.

Keeping this in view, what is considered a sub panel?

An electrical subpanel, also known as a service subpanel or circuit breaker subpanel, acts as a waypoint between the main service panel and branch circuits further down the line. Branch wire circuits lead off of the circuit breakers into various parts of the house.

What is the six disconnect rule?

The rule is six disconnecting means for each service, not six service disconnecting means per building. If the building has two services, you can have a total of 12 service disconnects (six disconnects per service).

27 Related Question Answers Found

Does a sub panel require a ground rod?

Yes. ALL sub-panels in detached buildings require at least one, and sometimes two, grounding electrodes, aka ground rods. Whether or not you need two depends upon the soil conditions and the LOCAL code requirements.

Why do you separate grounds and neutrals in a sub panel?

The neutral wire carries current. So bonding the neutral to the ground in a subpanel will allow current to flow over the ground wire back to the main electrical panel. So bonding the neutral to the ground in a subpanel will allow current to flow over the ground wire back to the main electrical panel.

How many sub panels are allowed?

You can have a million "sub panels" with a hundred-million ampere connected load all fed from your 200 ampere rated service as long as the total demand of all the panelboards combined does not exceed 160 amperes.

Can you run a sub panel off a subpanel?

Yes, it's redundant, but it's still required. The wire feeding the new subpanel must be protected from overcurrent by an appropriately-sized breaker. If using both, 1 must be sized for the conductor, and the other can be that size or larger -- convenient if you buy a panel with a 100A breaker preinstalled.

Can I run a 100 amp sub panel off 200 amp main?


If you already have 200- or 300-amp service, it is generally not a problem to install a 60-amp or 100-amp subpanel, but a service upgrade will likely be necessary if you have just 60-amp or 100-amp service.

What kind of wire do you use for a sub panel?

A subpanel requires two hot wires connected to a 240-volt double-pole breaker in the main panel. It also needs a neutral wire and a ground wire. The cable used for this run is known as a "three-wire cable with ground." The two hot wires, called feeder wires, will provide all of the power to the subpanel.

How do you build a sub panel?

In the subpanel, route the feeder wires, cut and strip them, and connect to terminals. Connect the black and red wires to the hot bus bars, the neutral wire to the main neutral terminal, and the ground wire to the ground bus bar.

Does sub panel wire need to be in conduit?

Re: Subpanel wire run
Individual THHN conductors must be run in conduit--either metallic or non-metallic, flexible or rigid. You could probably use SER instead, as long as it's sheathed and contains four conductors: one for Leg A, Leg B, neutral, and ground.

Does sub panel need main breaker?

Subpanel main breaker
A main breaker on a sub-panel is not necessary because this is in the same building (if you are in a different building then NEC 225.31, 225.32, 225.33 apply). That said, having a main breaker in the sub-panel is also acceptable.

Does a bonding screw have to be green?


NEC Article 250.28 (B) clearly states that the bonding screw (either the Main Bonding Jumper and/or the System Bonding Jumper) must be green in color and that it must be visible when installed.

How do you separate neutral and ground in a subpanel?

If we bond the ground wire to the neutral in the sub-panel, current will flow on both the neutral AND on the ground wire. Which means that if you do not keep the ground wires separate from the neutral wires, you will be allowing return currents to flow on the ground wires back to the main panel.

How do you size a sub panel?

Subpanel Circuit Breaker Sizing
To calculate the breaker size, simply divide the adjusted wattage by 240 volts to find the rated amperage needed for your subpanel. Often, the result is not a common circuit breaker size. and you can simply round up to the next higher size of ?the breaker.

What is the main panel?

A main panel (or service entrance panel) is simply a panelboard that contains the main service disconnect for a property -- this can be up to six circuit breakers in a rule-of-six (split bus) panel, but is more commonly a single main circuit breaker or fused disconnect (such as a pullout).

What size wire do I need for a 60 amp service?

That would be 4-gauge wire. In practice, however, it's common to wire 60-amp breakers with 6-gauge, 3-conductor wire because an appliance that needs a 60-amp breaker seldom draws the full 60 amps. If you're installing a 60-amp subpanel, however, it's best to connect it to the main panel with 4-gauge wire.

Can you run a 100 amp sub panel off a 100 amp main panel?


To the best of my understanding, there is no code issue running a 100A subpanel off a 100A main panel, so long as the wire size is correct, and the installation is correct. For a subpanel, you need four wire service (two hots, a neutral, and an equipment ground).

Can you feed a 100 amp sub panel with a 60 amp breaker?

You don't have to use a 60 amp panel. Use a 100 amp panel and feed it from a 60 amp breaker. The sub panel only has to be rated at or above the breaker size feeding it.

How many circuits can be on a 30 amp sub panel?

The circuit on the main panel feeding the garage has a two pole breaker labeled 30 amps. The garage sub panel has a one 20 amp circuit and one 15 amp circuit. There is room on the panel to add two more circuits.