Only suitable for use as service equipment?

[ggunn]

I have a situation where in order to interconnect a PV system to a service the AHJ requires us to bring the service up to current code. This means that we must install a main service disconnect ahead of the existing MLO MDP. The MDP nameplate is stamped "SUITABLE ONLY FOR USE AS SERVICE EQUIP". What does this mean? I thought that equipment suitable as service equipment could be used either as service equipment or not.

 

[wwhitney]

It's a term from the UL 67 listing standard that means the equipment comes from the factory with the neutral terminal bonded to the case, and no provision for removing that bond.

So you can't use it after a service disconnect as is. Maybe the manufacturer would be willing to provide instructions for installing a neutral bar isolated from the case, along with a new plaque. Otherwise I believe you will have to replace the panel.

Cheers, Wayne

 

[ggunn]

It's a term from the UL 67 listing standard that means the equipment comes from the factory with the neutral terminal bonded to the case, and no provision for removing that bond.

So you can't use it after a service disconnect as is. Maybe the manufacturer would be willing to provide instructions for installing a neutral bar isolated from the case, along with a new plaque. Otherwise I believe you will have to replace the panel.

Cheers, Wayne

Don't we have the option of not bonding N to G in the service disconnect?

 

[jim dungar]

Don't we have the option of not bonding N to G in the service disconnect?

Yes, but the type of equipment can impact that choice.

 

[ggunn]

Yes, but the type of equipment can impact that choice.

Can you elaborate on that?

 

[jim dungar]

Can you elaborate on that?

Suitable only for use as service entrance means the equipment is not rated to be used in a situation/location which requires the neutral and ground to be isolated from each other.

 

[wwhitney]

Don't we have the option of not bonding N to G in the service disconnect?

I don't think so, 250.24(B) says (2017):

"For a grounded system, an unspliced main bonding jumper shall be used to connect the equipment grounding conductor(s) and the service-disconnect enclosure to the grounded conductor within the enclosure for each service disconnect in accordance with 250.28."

I don't see anything in the exceptions to 250.24(B) or in 250.28 that would allow you not to bond N and G in the service disconnect.

Cheers, Wayne

 

[ggunn]

Suitable only for use as service entrance means the equipment is not rated to be used in a situation/location which requires the neutral and ground to be isolated from each other.

That wasn't my question. Do we not have the option of bonding N to the enclosure in the service disconnect and leaving N bonded to G in the MDP?

(posted before seeing Wayne's reply; looking at the 2020 NEC)

 

[wwhitney]

If the AHJ is requiring you to comply with 2020 230.71(B), which the MLO service panel no longer does, then you'll be installing a new service disconnect, and the MLO panel will no longer be service equipment. You'll have to change the panel one way or the other.

If the AHJ is requiring you to comply with 2020 230.85, and doesn't care about the 230.71(B) non-compliance, then you could install a new "emergency disconnect, not service equipment," and the existing MLO panel would still be service equipment, no changes required.

Cheers, Wayne

 

[ggunn]

If the AHJ is requiring you to comply with 2020 230.71(B), which the MLO service panel no longer does, then you'll be installing a new service disconnect, and the MLO panel will no longer be service equipment. You'll have to change the panel one way or the other.

If the AHJ is requiring you to comply with 2020 230.85, and doesn't care about the 230.71(B) non-compliance, then you could install a new "emergency disconnect, not service equipment," and the existing MLO panel would still be service equipment, no changes required.

Cheers, Wayne

The AHJ is requiring us to be compliant with their updated service design criteria, which requires a service disconnect and disallows PV connection to an MLO MDP. I expect that we will have to go to Eaton with the equipment details and inquire if and how we can reconfigure the panel.

 

[Strathead]

I don't think so, 250.24(B) says (2017):

"For a grounded system, an unspliced main bonding jumper shall be used to connect the equipment grounding conductor(s) and the service-disconnect enclosure to the grounded conductor within the enclosure for each service disconnect in accordance with 250.28."

I don't see anything in the exceptions to 250.24(B) or in 250.28 that would allow you not to bond N and G in the service disconnect.

Cheers, Wayne

I am glad you looked this up. I agree with your answer and it was my knee jerk reaction when I read the previous post, but I was too lazy to look it up. Basically the grounding electrode conductor can be bonded to the grounded wire anywhere from the service point to the first means of disconnect, but the neutral equipment ground bond must be at the first means of disconnect.

 

[ggunn]

I don't think so, 250.24(B) says (2017):

"For a grounded system, an unspliced main bonding jumper shall be used to connect the equipment grounding conductor(s) and the service-disconnect enclosure to the grounded conductor within the enclosure for each service disconnect in accordance with 250.28."

That language is unchanged in the 2020 NEC.

 

[electrofelon]

The AHJ is requiring us to be compliant with their updated service design criteria, which requires a service disconnect and disallows PV connection to an MLO MDP. I expect that we will have to go to Eaton with the equipment details and inquire if and how we can reconfigure the panel.

By "requires a service disconnect" you mean they do not allow supply side connections?

 

[electrofelon]

That wasn't my question. Do we not have the option of bonding N to the enclosure in the service disconnect and leaving N bonded to G in the MDP?

250.142(B) has a few exceptions, one is for "meter enclosures" but unfortunately that is as close as you will get .

I thought I had a loophole: installing a service disconnect only (NF safety switch, no overcurrent protection), so your MDP would still be service equipment as it is your overcurrent protection, but unfortunately the wording is such that the N- G must be separated after the "service disconnect", not "service equipment"

 

[ggunn]

By "requires a service disconnect" you mean they do not allow supply side connections?

No, they do, but the service is now an MLO panel with no OCPD ahead of it. In order to install PV they require that we bring the service up to current code, which requires a service disconnect. Once we do that we can connect the PV on the line side of the MSD.

The MLO panel has the SUITABLE ONLY FOR USE AS SERVICE EQUIP designation.

 

[electrofelon]

No, they do, but the service is now an MLO panel with no OCPD ahead of it. In order to install PV they require that we bring the service up to current code, which requires a service disconnect. Once we do that we can connect the PV on the line side of the MSD.

The MLO panel has the SUITABLE ONLY FOR USE AS SERVICE EQUIP designation.

Ok, so even if you dont touch the MDP, they are requiring it brought up to code. Thats lame.

 

[electrofelon]

It's a term from the UL 67 listing standard that means the equipment comes from the factory with the neutral terminal bonded to the case, and no provision for removing that bond.

So you can't use it after a service disconnect

just thinking about this and my "idea" in post #14: kinda interesting that UL's definition of "service equipment" and the NEC's definition are not in sync. It also seems strange that a manufacturer would limit the use of their equipment by seeking or building it such that it gets a SUOSE label.

 

[wwhitney]

It also seems strange that a manufacturer would limit the use of their equipment by seeking or building it such that it gets a SUOSE label.

I'm going to guess that in order for it to get a SUSE label, there would need to be space for a field installable neutral bar isolated from the enclosure, which in some cases would require a larger enclosure. So they go for a SOUSE label to avoid upsizing the enclosure.

But that's a total guess.

Cheers, Wayne

 

[jaggedben]

That wasn't my question. Do we not have the option of bonding N to the enclosure in the service disconnect and leaving N bonded to G in the MDP?

Specifically what prohibits this is 250.24(A)(5). 250.142 also. (The latter has some exceptions that don't apply to your situation.)

 

[jaggedben]

The AHJ is requiring us to be compliant with their updated service design criteria, which requires a service disconnect and disallows PV connection to an MLO MDP. I expect that we will have to go to Eaton with the equipment details and inquire if and how we can reconfigure the panel.

Another option might be to have the installation of an isolated neutral field listed by UL.