Optional stand by whole house generator (2020 nec code change requirements)

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Bthespark05

New User
Location
Massachusetts
Occupation
Journeyman electrician
Hi I live out here in Massachusetts where we have adopted the 2020 nec code changes. I've been looking for some clarification on optional whole house stand by generators.
Let's say you have an existing 100 amp underground service with a remote meter pedestal. The conduits come through the foundation into the back if the panel. I unsecure the panel and move it over enough to install the whole house transfer switch and then nipple into the existing panel. The generator is a 22kw.
Does this mean I have to now install a 100amp main fused disconnect on the outside of the house? Either remove meter socket and install a meter main, a nema 3 main breaker beside meter socket or below, dig up the conduit at the house and reroute it to a main breaker on the side of the house and then run a #2 ser into the transfer switch?
Also does a rapid emergency shut down switch have to be located "grouped" next to the service main disconnect?
These are some of the things I'm hearing, but some towns say you dont need to do the main breaker if it's an existing service. I know you do have to have a 2nd emergency shut down switch for the generator if it's over 14kw.
Some of the articles I have found that relate to this topic are 230.85 emergency disconnect for service needed, and 445.18D emergency disconnect for generator required.
Any inputs would be appreciated. I've talked with multiple inspectors who say you dont need to do the service disconnect if it's an existing service and a couple that say you do. I wish the code was more black and white so it's not left up for multiple interpretations. Thanks for reading!
 
RD35

RD35

Senior Member
Location
Bloomington, Indiana
Regardless of what the NFPA 70 states, the authority having jurisdiction (AHJ)has the final say on the matter. I would suggest you go to the inspector for the project and ask for a ruling. For the sake of my reply I will state some assumption I am making based on your post.

Assumption #1: Remote meter pedestal is a meter socket mounted on the outside wall of the house with a service feed running down underground and into the back of a service panel located on, say, the basement wall.

Assumption #2: Generator is a Generac Guardian Series 22KW ground mounted, hardwired, unit.

Assumption #3: Transfer switch will be a Generac automatic switch matched to the generator.

If I have this correct then here we go. 445.18 (A) states a requirement for a disconnecting means. 702.12 adds that the disconnecting means called for in 445.18(A) must be "within sight" which means within 50 feet of the building and visible. The generator has a circuit breaker disconnect inside the enclosure door that meets this requirement. If the generator is located more that 50ft from the building then you will need an additional disconnect within sight (usually mounted on the building nearest the point of entry of the generator circuit conductors.).

Now as for the service entrance conductors, the transfer switch can be purchased as a "service entrance rated" switch and will have a utility main breaker inside. This switch will also have a bonding jumper inside that bonds the neutral to the grounding system. So you will need to separate the neutrals and grounds in the panel and remove the bonding jumper inside the panel as it will no longer be a service panel.

If you are not using a service rated transfer switch you will need to install a service rated switch or enclosed breaker ahead of the transfer switch. (you will still need to separate neutrals and grounds in the panel and remove the bonding jumper.

With the service switch (service rated transfer switch) located adjacent to the existing service panel, some AHJ's will allow you to remove the bonding jumper inside the transfer switch and leave the bond in place inside the panel. This way you don't have to do all the work of re-wiring to separate neutrals and grounds. It depends on the inspector.

As for the shutdown 445.18 (B) calls for a control switch that will shut down the generator while also disabling any start circuits and that will require a mechanical reset. 445.18 (C) calls for the switch to be located outside the generator room or enclosure. The 22KW Generac Guardian system (assuming this is what you have) has a toggle switch on the outside of the generator enclosure that meets all of those requirements.

I hope this helps and I hope other more knowledgeable folks will jump in if I've missed anything.
 
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shortcircuit2

Senior Member
Location
South of Bawstin
Massachusetts has determined if you are replace the service disconnect, then you must comply with 230.85.

Massachusetts has determined if you replace any other part of a service, other than the service disconnect, you do not need to comply with 230.85.

Although good practice, there is no rule for ED grouping. But directories and placarding is required.

IMO, the prime mover shutdown satisfies 2020 445.18(D)
 
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shocksystems

Member
Location
Massachusetts, USA
Occupation
Electrician
shortcircuit2 said:
Massachusetts has determined if you are replace the service disconnect, then you must comply with 230.85.

Massachusetts has determined if you replace any other part of a service, other than the service disconnect, you do not need to comply with 230.85.

Although good practice, there is no rule for ED grouping. But directories and placarding is required.

IMO, the prime mover shutdown satisfies 2020 445.18(D)
Click to expand...

This makes sense. So in the case that Bthespark05 mentions above (adding a transfer switch between meter socket and the main disconnect electrical panel) an external disconnect would be required?
 
M

Mdsparky

Member
Location
massachusetts
Occupation
electrician
shortcircuit2 said:
Massachusetts has determined if you are replace the service disconnect, then you must comply with 230.85.

Massachusetts has determined if you replace any other part of a service, other than the service disconnect, you do not need to comply with 230.85.

Although good practice, there is no rule for ED grouping. But directories and placarding is required.

IMO, the prime mover shutdown satisfies 2020 445.18(D)
Click to expand...
Where is this determination found ?
I live North of Bawstin
 
sparky1118

sparky1118

Senior Member
Location
Massachusetts
Occupation
Master Electrician
Bthespark05 said:
Hi I live out here in Massachusetts where we have adopted the 2020 nec code changes. I've been looking for some clarification on optional whole house stand by generators.
Let's say you have an existing 100 amp underground service with a remote meter pedestal. The conduits come through the foundation into the back if the panel. I unsecure the panel and move it over enough to install the whole house transfer switch and then nipple into the existing panel. The generator is a 22kw.
Does this mean I have to now install a 100amp main fused disconnect on the outside of the house? Either remove meter socket and install a meter main, a nema 3 main breaker beside meter socket or below, dig up the conduit at the house and reroute it to a main breaker on the side of the house and then run a #2 ser into the transfer switch?
Also does a rapid emergency shut down switch have to be located "grouped" next to the service main disconnect?
These are some of the things I'm hearing, but some towns say you dont need to do the main breaker if it's an existing service. I know you do have to have a 2nd emergency shut down switch for the generator if it's over 14kw.
Some of the articles I have found that relate to this topic are 230.85 emergency disconnect for service needed, and 445.18D emergency disconnect for generator required.
Any inputs would be appreciated. I've talked with multiple inspectors who say you dont need to do the service disconnect if it's an existing service and a couple that say you do. I wish the code was more black and white so it's not left up for multiple interpretations. Thanks for reading!
Click to expand...

Just ask the local AHJ of the town you’re working in. Like you said the inspectors are all over the board with this topic.


Sent from my iPhone using Tapatalk Pro
 
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shocksystems

Member
Location
Massachusetts, USA
Occupation
Electrician
M

Mdsparky

Member
Location
massachusetts
Occupation
electrician
shortcircuit2 said:
Follow the TIA language.

The TIA is posted here...along with the 2020 Massachusetts Amendments:

Massachusetts Electrical Code

Here you'll find information relating to the Massachusetts Electrical Code.
www.mass.gov www.mass.gov
[/QUOTE
Click to expand...
from the TIA ;
This section shall only apply to the following: (1) New one- and two-family dwellings, or new buildings of double occupancy, at least one of which is a dwelling unit. (2) Two-family dwellings or buildings of double occupancy at least one of which is a dwelling unit, and newly created by subdivision of an existing one-family dwelling. (3) One- and two-family dwellings where the service(s) is (are) entirely replaced. (4) One- and two-family dwellings where the service(s) is (are) increased in capacity in terms of its (their) rating in amperes
 
S

shocksystems

Member
Location
Massachusetts, USA
Occupation
Electrician
Mdsparky said:
from the TIA ;
This section shall only apply to the following: (1) New one- and two-family dwellings, or new buildings of double occupancy, at least one of which is a dwelling unit. (2) Two-family dwellings or buildings of double occupancy at least one of which is a dwelling unit, and newly created by subdivision of an existing one-family dwelling. (3) One- and two-family dwellings where the service(s) is (are) entirely replaced. (4) One- and two-family dwellings where the service(s) is (are) increased in capacity in terms of its (their) rating in amperes
Click to expand...

Thanks I missed that. Also the accompanying letter certainly explains that they are attempting to get rid of this uncertainty of when it applies.
 
S

shortcircuit2

Senior Member
Location
South of Bawstin
Exception to (1), (2), and (3): A building supplied by a service lateral or by underground service conductors shall be permitted to be capable of disconnection from a readily accessible location outside of the dwelling by using a method providing remote control of the service disconnecting means, and marked: EMERGENCY ELECTRICAL DISCONNECT and NOT SERVICE EQUIPMENT.

Also added is a remote control option. This was needed in areas of Boston where it is not possible to put disconnect outside. Shunt trip the main.
 
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