This is how I understand a res service is done. If the MBJ in the main panel is removed, I’d have to isolate grounds and neutrals correct?

Status
Not open for further replies.
SomeRandomPerson said:
Thanks Jon
Now the labeling gets me a bit confused to. Couldn’t the meter main be considered both and “emergency and a service disconnect” and when do you know which applies?


Sent from my iPhone using Tapatalk
Click to expand...
Yes, if the service disconnect is outside then you don't need a separate 'emergency disconnect'. But they wrote the new emergency disconnect requirement (230.85) to allow it to be a disconnecting means ahead of the regular service equipment, meaning that the latter can be inside and still be where your MBJ is and where your GEC lands if you want.

(I have said elsewhere that I think 230.85 was a very bad idea. The additional confusion that it causes newbies like you is just one of the reasons.)
 
wwhitney said:
I didn't check your references, but I don't see any inherent conflict. The point of the GES is to earth the neutral, so it doesn't matter where that happens between the service entrance and the main panel. The point of the MBJ is to let the EGC system clear a fault (for grounded systems), so it occurs where the EGC originates. The EGC's connection to the GES is a side effect, not the purpose of the GEC.

Cheers, Wayne
Click to expand...
The neutral cannot be earthed at a 'main panel' (not a code term) that is not service equipment. It can be earthed at the service equipment or anywhere on the line side.
 
jaggedben said:
Yes, if the service disconnect is outside then you don't need a separate 'emergency disconnect'. But they wrote the new emergency disconnect requirement (230.85) to allow it to be a disconnecting means ahead of the regular service equipment, meaning that the latter can be inside and still be where your MBJ is and where your GEC lands if you want.

(I have said elsewhere that I think 230.85 was a very bad idea. The additional confusion that it causes newbies like you is just one of the reasons.)
Click to expand...

You got that last part right! But it’s even confusing some of the journey men I work with. It’s partly why I’m confused as well. I just need to find a good picture of how it’s done properly but no luck yet


Sent from my iPhone using Tapatalk
 
ActionDave said:
The way I see it in the drawing in the OP the neutral is earthed at two spots. There should be only one GEC connection at one.
Click to expand...
I agree that's best practice, but I believe the code allows multiple GEC connection points as long as none are load side of the service equipment. I don't have the book with me and I don't think it's crystal clear.
 
jaggedben said:
I agree that's best practice, but I believe the code allows multiple GEC connection points as long as none are load side of the service equipment. I don't have the book with me and I don't think it's crystal clear.
Click to expand...
That is correct. You can connect the ground rods at the meter and the water pipe at the panel or service disconnect.
 
SomeRandomPerson said:
Does either instance make labeling at the meter main change from emergency disconnect or service disconnect ?
Click to expand...
Kinda yes but not really. All the pieces just have to match. If you do your grounding with one idea but your MBJ with another then something has gotta change.

Service equipment is (coming from the utility direction toward the home):
-where your MBJ is
-the last place that you bond ground and neutral together
-the last place that you connect the neutral to earth (with a grounding electrode conductor)

A separate 'emergency disconnect' can be on the line side of that place.

Also btw the NEC does not care where the meter is or even if there is one. Meter placement is subject only to utility rules.
 
Dennis Alwon said:
I don't think you can do that. If the unit is labeled by the manufacturer as service equipment you can't just write on the panel non service equipment.
Click to expand...
wwhitney said:
That could possibly be an issue if it is labeled as "Suitable Only for Use as Service Equipment."

But if it's labeled as "Suitable for Use as Service Equipment" there shouldn't be any issue.

Cheers, Wayne
Click to expand...
That's the problem with the new rule not taking into account all of the old rules. The Suitable Only for Use as Service Equipment would have a factory bonded neutral (a bonded neutral is required if it's being used as an emergency disconnect) but if it is not service equipment then it cannot be used as the EM disco.
 
infinity said:
That's the problem with the new rule not taking into account all of the old rules. The Suitable Only for Use as Service Equipment would have a factory bonded neutral (a bonded neutral is required if it's being used as an emergency disconnect) but if it is not service equipment then it cannot be used as the EM disco.
Click to expand...
I'm happy to side step the terminological conflict by simply noting that "suitable only for use as service equipment" is not an NEC term (I didn't find that phrase anywhere in the 2017 NEC), it's a UL term. So it's just a UL-NEC coordination issue, and there's no reason that NEC "service equipment" and UL "service equipment" have to mean the same thing. The latter can just be read as "the service disconnect or anything on its line side."

But it would be nice if the NEC resolved this terminological conflict by changing the wording in 230.85, or if UL did so by changing the wording that denotes the neutral terminal is permanently bonded to the case.

Cheers, Wayne
 
wwhitney said:
I'm happy to side step the terminological conflict by simply noting that "suitable only for use as service equipment" is not an NEC term (I didn't find that phrase anywhere in the 2017 NEC), it's a UL term. So it's just a UL-NEC coordination issue, and there's no reason that NEC "service equipment" and UL "service equipment" have to mean the same thing. The latter can just be read as "the service disconnect or anything on its line side."

But it would be nice if the NEC resolved this terminological conflict by changing the wording in 230.85, or if UL did so by changing the wording that denotes the neutral terminal is permanently bonded to the case.

Cheers, Wayne
Click to expand...
It certainly could be applied that the wording in the listing "suitable only for use as service equipment" cannot be used for non-service equipment.
 
230.85 should just be deleted in its current form.. Start over. Try again. Require service equipment to be outside, with a giant exception for existing installations for where only the service equipment is being replaced.
 
jaggedben said:
230.85 should just be deleted in its current form.. Start over. Try again. Require service equipment to be outside, with a giant exception for existing installations for where only the service equipment is being replaced.
Click to expand...

Maybe the next code cycle....

But seriously, what do you guys do on a residential service?


Sent from my iPhone using Tapatalk
 
SomeRandomPerson said:
Maybe the next code cycle....

But seriously, what do you guys do on a residential service?


Sent from my iPhone using Tapatalk
Click to expand...
It depends on where you grew up and where you broke into the electrical trade. It is a totally emotional decision.

I'm from the west and you always see a an outside service disconnect. Start moving to the east and outside disconnects freak electricians out so much that given the choice between putting a service disconnect outside and chopping off a leg most would choose chopping off a leg.
 
ActionDave said:
It depends on where you grew up and where you broke into the electrical trade. It is a totally emotional decision.

I'm from the west and you always see a an outside service disconnect. Start moving to the east and outside disconnects freak electricians out so much that given the choice between putting a service disconnect outside and chopping off a leg most would choose chopping off a leg.
Click to expand...

Can confirm. I’m in Boston. Seems some of my journeymen feel as if this requirement is the end of the world and others think it’s only the beginning of the end of the world.
And here I am, green as a spring flower wondering where to land my EGC from my water meter.


Sent from my iPhone using Tapatalk
 
SomeRandomPerson said:
Can confirm. I’m in Boston. Seems some of my journeymen feel as if this requirement is the end of the world and others think it’s only the beginning of the end of the world.
And here I am, green as a spring flower wondering where to land my EGC from my water meter.


Sent from my iPhone using Tapatalk
Click to expand...
I hope it’s the GEC you wonder about.

Below meter disconnects on the pole are common. Some are or were supplied by the POCO. Some areas have Meter with Transfer switches below. We’ve always been able to ignore them. They were just a switch. Not Service Disconnects.
 
ptonsparky said:
I hope it’s the GEC you wonder about.

Below meter disconnects on the pole are common. Some are or were supplied by the POCO. Some areas have Meter with Transfer switches below. We’ve always been able to ignore them. They were just a switch. Not Service Disconnects.
Click to expand...

Hahaha. Yes, Grounding electrode conductor from the water main.
I think if that terminated in the main panel, the ground rods terminated in the meter main outside and the main bonding jumper was installed in the panel then you wouldn’t have to separate grounds and neutrals in the main panel ?


Sent from my iPhone using Tapatalk
 
Status
Not open for further replies.
Top