Electrical Panel Upgrade-National Electrical Code requirements

A Licensed electrician or/and the homeowner are required to reach out to the utility company to spot the meter location, even if the existing meter seems perfect for you, the utility company has to come and approve the location first, depending on the location of the utility electrical pole.

The service disconnecting means shall be installed at a readily accessible location (as defined in CEC Article 100) either inside or outside of a building or structure or inside nearest the point of entrance of the service conductors. (CEC 230.70(A)(1)) , NEC 230.70 (A)(1).

Electrical panel upgrade permit

A Licensed electrician or/ the homeowner needs to apply for electrical panel upgrade permit and call for service panel inspection in order to get the release of your new service meter, because without the city/county releasing your new electrical panel, the utility company will not show up and release your meter.

What is the minimum size main breaker for any dwelling unit?

A minimum of 100 Amps main breaker is required for any dwelling unit per NEC and California electrical code.

Residential feeders conductor size

Service or Feeder Rating
Size of main breaker Conductor Copper(AWG/Kcmil)Size of main breaker Conductor Aluminum or
Service feeder conductor (wire) size Per NEC 2017-310.15(B)(7)

Residential Electrical Panel Grounding requirements

Service or Feeder Rating
Size of Grounding
Electrode Conductor Copper(AWG/Kcmil)
Size of Grounding
Electrode Conductor aluminum(AWG/Kcmil)
125 86
200 42
Grounding Electrode conductor (wire) size Per NEC 2017-(Table 250.66)
#4 Copper Grounding
Electrode Conductor

Residential service panel grounding methods

1. Ufer ground

UFER is usually used in the new construction when pouring a new footing. The UFER ground is a minimum of #4 rebar, 20 feet long in concrete per (CEC 250.52 (A)(3)) & (NEC 250.52(A)(3)) or o 20’ of minimum 4 AWG bare copper wire.

UFER Ground
UFER With an access Panel

2. Ground rod

One ground rod 8 ft. long is required to be used as the primary grounding system, The rod consist of one of the following according to CEC 250.52 (A)(5)) & NEC 250.52 (A)(5)),

  • Pipe or conduit not smaller than 3/4” in diameter.
  • stainless-steel and copper or zinc coated steel not smaller than 5/8” in diameter.

In many cases the authority having jurisdiction ask for two ground rod 6 ft. apart minimum. If a single rod, pipe, or plate grounding electrode has a resistance to earth of 25 ohms or less, the supplemental electrode shall not be required.

A ground rod 5/8'' used as a primary grounding system
A ground rod 5/8” used as a primary grounding system

3. Main water line grounding

Connecting the ground conductor to the main water line within 5 feet where the water line enters the house and it can be used as a grounding system but not as the primary, an additional ground rod is required with the water pipe.

The water pipe shall be a minimum of 3/4” inch.(CEC 250.68(C)) & (NEC 250.68(C)).

main water line is used as a grounding system
main water line is used as a grounding system

Panel bonding requirements

In addition to the grounding requirements, some cities and counties require the gas to be bonded. Which mainly happens at the water heater, a ground wire connects the cold and hot water lines with the gas line (CEC 250.104).

However, if the water system in the house is not metallic such as galvanized steel or copper, the bonding will not work. The bonding conductors or jumpers shall be sized in accordance with (CEC 250.122) (NEC 250.122).

Bonding Conductors Size -Table 250.122

Service or Feeder Rating
Copper(AWG/Kcmil)Aluminum or

Difference between grounding and bonding

NEC and California electrical code prohibits the grounding of the gas line.

Grounding is a direct continuous connection from the main panel bus bar to one of the three grounding system I mentioned above (UFER, Ground rod, and water line ), Gas bonding is a connection from a grounding system to the gas line.

Electrical Panel service clearance

Main panels and sub panels shall have a minimum of 36 inches clearance in front of it, measured from the live parts not the face of the panel which is a common mistake between the building inspector and the electrician.

It also requires 30 inches width and 6 ft. and 6 inches high measured from the finished grade.(CEC 110.26).

electrical panel working space clearance , service panel clearance

What is the maximum height of a circuit breaker?

A 6 feet and 7 inches (79 inches) is the maximum height of a breaker slot inside the electrical panel even if it is not used, it is measured from the finished grade.

Electrical meter riser (Service Mast)

The riser (service mast) should be strapped and supported according to (230.28 (A)(B)) NEC 2017.

electrical panel mast(riser)
A service mast is strapped

Electrical panel unpermitted Locations

The NEC prohibits the electrical boxes ( Sub-Panel, main Panel ) to be installed inside the clothes closet, bathroom, above steps of stairway.

A common question if a sub-panel can be used inside a laundry room? the answer is, yes if it meets the minimum service Clearance per NEC & (CEC 240.24).

Circuits Breaker labeling

Each circuit in the panel must be identified with a circuit directory that is located on the face or inside of the panel door (CEC 408.4(A)). Label shall be clear and permanent.

Sub-Panel installations

Here is an example of the installation of a sub panel , the neutral wires and grounding wires shall not be on the same bus bar (CEC 250.6, CEC 250.32(D)(1), as the picture shows the neutral bus bar sets on a plastic sheet isolate it from the the frame of the metal sub panel box.

Sub Panel installations
Sub Panel installations

Electrical Panel Upgrade Cost

The average cost to upgrade your electrical panel starts at $1000 and up, it depends on the panel amperage, location of the new electrical meter, and if any branch circuits need a rewire. The average hourly wage for an electrical between $40 to $100.

Main Breaker Amperage SizeCost
100$1000 – $1500
200$1000 – $2000
400$2000 – $4000

Reference Codes – National Electrical Codes – California Electrical Code

2 thoughts on “Electrical Panel Upgrade-National Electrical Code requirements”

  1. This is some really good information about electrical panels. It is nice to know that it would be smart to check the location of the panel is permitted. I didn’t’ realize that could be an issue with a panel. I would want to get it done properly.

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