Service Disconnects: How Many and Where to Put Them. What’s New For 2020?
By: Jerry Durham | Feb 01, 2021
NEC Section 230.71. Six Switches or Circuit Breakers in One Enclosure
Since the 1937 edition of the NEC, the service disconnecting means used to isolate a building’s premises wiring from the utility provider’s conductors has been allowed to consist of as few as one, but as many as six switches or sets of circuit breakers.
A veteran electrician would tell you that requirement (or permission, depending on your perspective) means six throws of the hand can be used to control all power on the property. Our veteran electrician is correct – if there is one electrical service on the property.
The long-standing permission from the NEC to install up to six switches or circuit breakers or a combination thereof as the service disconnect for an electrical service remained uncontested through the 2017 Code cycle as long as:
- The switches or circuit breakers occupied the same electrical enclosure, or
- The switches or circuit breakers were installed in six separate enclosures but remained in a group together.
The message the NEC was sending was clear, the electrician could install six switches or circuit breakers to control the electrical service, but those control devices had to stay together in one location.
What Has Changed for the 2020 NEC?
NEC Section 230.71 has undergone a significant overhaul for the 2020 Code cycle, namely, the omission of the previous permission to install six switches or sets of circuit breakers acting as service disconnect, in a single enclosure.
You are still allowed four, five, or even six switches or circuit breakers to act as the one service disconnect, but those control devices must now be installed within individual enclosures.
NEC 230.71 Maximum Number of Disconnects 2017 NEC vs. 2020 NEC
In the 2017 Code cycle, Section 230.71(A) allowed up to six switches or sets of circuit breakers to serve as the service disconnect as long as all control devices were installed within a single electrical enclosure or in separate enclosures, while the enclosures remained grouped.
In the 2020 Code cycle, Section 230.71(B) also allows up to six switches or sets of circuit breakers to serve as the main disconnect for one service, if they consist of a combination of any of the following:
- Separate enclosures with a main service disconnecting means in each enclosure.
- Panelboards with a main service disconnecting means in each panelboard enclosure.
- Switchboards where there is only one service disconnect in each separate verticle section where there are barriers separating the sections.
- Service disconnects in each switchgear or metering center where each disconnect is located in a separate compartment.
Section 230.72(A) then goes on to tell the electrician to group all of these individual enclosures acting as one service disconnect, and to mark each to indicate the load being served.
What 230.71 in the 2020 NEC fails to do is give the electrician the same permission enjoyed since 1937 to install these six switches or sets of circuit breakers in one single electrical enclosure.
Gone are the days of installing four, five, or even six two-pole circuit breakers in a single outdoor enclosure to control loads such as the dwelling’s load center, the garage panel, the AC condensing unit, the electric furnace, the pool pump, the hot tub on the deck, and so on.
Switches and Sets of Circuit Breakers
Unless you sleep with a Codebook under your pillow, you may have found yourself stopping for an unceremonious double-take at the NEC reference to “six sets of circuit breakers.”
Sets of circuit breakers?
Many of us have purchased a “set” of tires for our vehicles. Some of us may have sprung for a “set” of bookends, at one time, to tame the unruly stack of outdated Codebooks we refuse to part with – just in case. Or perhaps we even purchased a “set” of encyclopedias. But I have failed to meet anyone who has purchased a “set” of circuit breakers. Though I am sure, they can be found in an economical package of two!
What the NEC is referring to is a group of individual circuit breakers, perhaps two or even three, assembled to make one two-pole or three-pole overcurrent device.
Remember, the Code allows up to six throws of the hand to terminate power at an electrical service. This may include flipping a single-pole, two-pole, or even three-pole circuit breaker to complete the job.
The NEC in 2020 has erased our antiquated method of installing six circuit breakers in one enclosure to serve as a building’s service disconnect. The reason? Bundling multiple service disconnect switches inside one enclosure makes it impossible to comply with NFPA 70E Standards for Electrical Safety in the Workplace when it comes to safe work practices applied to service equipment.
While it may not seem convenient at present, this new revision to the Code allows electricians to flip a switch and terminate all power inside an enclosure for equipment servicing, making a safer work environment for all involved.
Brush up on the 2020 NEC and other industry essentials when you complete electrical continuing education. Courses are available for a significant number of states and can be completed entirely online. Connect with JADE Learning today to stay up to date on the latest technical, code-related news and topics.
6 thoughts on “Service Disconnects: How Many and Where to Put Them. What’s New For 2020?”
If I have a 200 amp meter main/combo with 6 2 pole spaces am I allowed to use this as a main disconnect under 230.71?
Also is a multi meter 4 pack or 6 pack serve as a disconnect or does it need a main breaker ahead of it ?
So basically you put a mcb outside at the service and you’re good to go. This also therefore requires you run a 4 wire feeder to inside panel and separate neutrals and grounds which is better anyway. Ive been doing it this way for years
You are correct. If you install a “main” circuit breaker or any one switch or fused-switch approved for use as service equipment on the outside of the dwelling, then you run a 4-wire feeder to the load center in the house or garage, as you described. And at the load center, you would separate the grounding and grounded conductors (aka neutrals). The switch outside would be the first means of disconnect (service equipment) and the service equipment is where we install the main bonding jumper that connects grounds and neutrals together. Also new for the 2020 NEC – the “Main” breaker or switch that you install outside will need to be marked with an “Emergency Disconnect” sticker in addition to the “Main” sticker that you normally place here. NEC 230.85 in the 2020 NEC requires an Emergency Disconnect to be installed for firefighters outside of every dwelling. Your normal service equipment installed outside can do this, but it must have the “Emergency” sticker applied to it as well.
Now, if you don’t wish to install a “Main” switch outside and you don’t wish to install your “Main” circuit breaker panel outside, then the 2020 NEC allows for a meter base with built-in emergency disconnect switch to be installed. You would have to mark it with the “Emergency Disconnect” sticker. The new 2020 Code says when the meter base with built-in switch is used as the “Emergency” disconnect, it is NOT to be considered the service equipment. So the main breaker panel in the house would still be your “Main” and would still be the service equipment where the main bonding jumper is installed.
Lots of new “stuff” coming our way from the 2020 NEC. Be sure to check out JADE Learning’s new NEC Challenge Subscription where we send you 2020 Code Q&A with full explanations of the 2020 Code changes, all year long to your phone or computer. It’s an inexpensive and easy way to learn the new 2020 NEC, from the experts!
Jerry – JADE Learning Instructor
Can I add a service disconnect from the meter to my ac unit?
I am rebuilding a vacation cottage so will need to install a new meter and 200 amp/240 volt service disconnect to comply with NEC 230.85.
• Can I use a Service Disconnect or does it have to be a circuit breaker? I have worked in industry for 50 years and found that circuit breakers fail more frequently in humid locations exposed to hot and cold ambient temperatures so I want to use a disconnect outside.
• Can I get a Service Disconnect that I can install a fireman’s lock in the ON position to ensure no vandals can turn the power off in the middle of winter. We won’t be around for much of the winter.
• Does the service disconnect have to be mounted on the outside of the house? I would like to install it with the meter on a backboard next to the garage as we will have underground conduit to the house.
• I want to install a generator to cover the frequent power outages powering only the furnace and heating recirc pumps through a subpanel. Can I install the transfer switch inside the house at my breaker panel?
Does the NEC allow for the main breaker/disconnect to located on a nearby meter pole?
My service provider requires a main breaker on the meter pole, directly beneath the meter or in a combo meter socket. But it sounds like the NEC requires a disconnect physically on the house.
Any issues with multiple main disconnects in series like this?