What is a service disconnect?

[Adamjamma]

I think basically I am trying to figure out if we can get a consensus or a reason for not requesting the following: If a disconnect is requested by local authorities on the outside of a building or at a meter ( the fire fighters disconnect) then this can be a non fused disconnect. This would not replace the main fused disconnect at the main panel, and can thus be fed from the meter to its position, and from it to the main panel and/or main OCPD under the regular single residence rules of feeding the main panel.
If a fused disconnect is used, this must become the main OCPD and the feeder rules then are in place from this position to the main panel and an OCPD may not be required at the main panel.

Of course, idiots like myself probably will put an OCPD at this position and at the main panel as well, just because it does protect the wire, and in Jamaica wire is very expensive, but...

Main reason I am looking at this is the island is looking at adopting the NEC as the majority of its code regulations. There will be a few modifications due to the closeness to UK and Canada, but hopefully pulling the better and not the worst parts of them in regards to the styles of building construction and weather problems on the island. Not trying to make anyone angry, just trying to understand more of the safety concerns of such systems, as the main difference comes down to the requirement that one, the meter be located on a pole constructed at the property line so the meter reader does not need to enter the property, two, that there be a panel on each floor in an accessible location that is not in a closet or behind a closed door, with OCPD on each panel, and the first panel from the meter being wired as the main panel, with the neutral and grounds separated after that panel in all other panels, but they must be fed from this panel, and now with the possible requirement to include an outside disconnect, that is grouped with disconnects for any solar, wind or other generation means, is able to be disconnected by fire fighters in case of emergency, but is lockable so as to keep vandalism at a minimum. The exact codes are not yet actually written to give us the basics but are only the suggested after the fire departments requested such switches after having some problems with certain house fires.
But, I am not sure how good such switches would be in a country that the average time of response for the fire department is two to three hours... yes, hours...
Already stated in the possible amendments to the NEC if adopted are the color codes of wires, the number of outlets per circuit in a kitchen, which they will not raise from three..lol... even with many of us asking for five... and the requirement that each floor have its own panel box, including any basement if accessible and having any outlets. Oh, and no panel box may be on an outside wall if the wall is concrete construction... laughed when I saw that one...

[jap]

It is more a question of why am I considering a firemans switch. The requirement for the neutral and four wire feeds and full ratings are fairly new in some ways. Well, guess it may go back to 90's but... residences were able to run 200 amp services on cables capable of running less than 200 amps from the meter to the main panel inside, whether overhead or underground. Suddenly, if a disconnect goes in between the meter and the main panel, so it can be turned off from outside the home, or from near the road on a long run like in the rural areas or places like I deal with in Jamaica, where the POCO wants meters visible from property line so they do not have to enter the property, the wiring from that disconnect must be four wire now. and at fill amps not the reduced amps. Which can add a lot more cost, especially when one adds in voltage drop. I have dealt with a property before where the customer had a meter at the driveway entrance from the road, with a disconnect on their post, and then had a half mile run along the driveway to a post in the center of their yard before splitting to feed 4 separate buildings, each treated as a main panel. To me a typical farm system. Disconnect at the meter post and disconnect at the central post in the main yard could both be used to disconnect the utility from the buildings in case of a fire. All of it run on three wires from the meter until you got to the buildings, with two disconnects that had no fuses in them. System at least thirty years old when I last saw it and worked fine.

To do a similar system would require heavier wire and a four wire system from what many are saying... between voltage drop and the requirement now to, at least from what I am reading, create a grounded and bonded system from the meter location along the half mile driveway to the buildings.. four wire from road to buildings as well. But is it actually any safer? Or is it just adding cost? The main reason for the disconnects at the road to the main post was so if a storm blew a tree down that took the wires down, one could disconnect the power, fix the wire, and turn the power back on. Main reason for disconnect at pole in yard was so one could change services at the various buildings or even add extra buildings to the services.

Of Course, now some farms have major three phase services supplying milk systems etc, but, most farms in Jamaica are not so advanced and with customs fees at the wharf may never get that advanced. However, fire department in Jamaica has asked if in future codes it could somehow be written to require a disconnect on the outside of all structures. Placed at no higher than 2.7 meters from either grade or sidewalk or pavement.

We too are required to have a disconnecting means on all of our structures being fed by electricity.
whether it ends up on the inside or outside is usually up to what the project allows and what is required by local ordinances.

Sometimes that disconnect can be as simple as a single pole light switch.

As far as in your scenario, the service disconnect they are talking about may be just that. A Non Fused disconnect for the 3 wire service conductors that they can seal off themselves to limit it's use.

Have you asked them, or, are you speculating that this is where the 4 wire feeder will have to begin ?


JAP>

[Craigv]

After the service point, the first disconnecting means and OCPD, which must be together, is the Service Equipment by NEC description/definition. The grounding electrode system must also be located here, which means everything past this is a feeder, requiring an equipment ground, thus the "4-wire feed".

If fire safety rules are incorporated into the local code, it is possible to require the Service Equipment to be located outside at a location accessible to emergency responders. In areas of the country where basements and crappy weather are rare, service equipment and main loadcenters are often outdoors. But even if the home has an indoor panel the service equipment with disconnect can be located outside.

[jap]

The power company here requires a disconnect ahead of the meter on 480v services so they don't have to bypass and pull the meter under a load.

They put their seal on it.

This is not considered our service disconnect where the overcurrent and bonding takes place.

I don't see this as being much different than what the OP's up against.

Jap>

[Craigv]

The power company here requires a disconnect ahead of the meter on 480v services so they don't have to bypass and pull the meter under a load.

They put their seal on it.

This is not considered our service disconnect where the overcurrent and bonding takes place.

I don't see this as being much different than what the OP's up against.

Jap>

They don't trust that a disconnect on the other side is equally capable of opening any closed circuits?

Must be PP&L......Paranoid Power & Light

[electrofelon]

They don't trust that a disconnect on the other side is equally capable of opening any closed circuits?

Must be PP&L......Paranoid Power & Light

Most meter sockets have bypass capability, either horn, block, or lever, so I don't think it's a load interrupting issue. I think they just want to be able to kill power to the meter socket.

[Adamjamma]

Have you asked them, or, are you speculating that this is where the 4 wire feeder will have to begin ?


JAP>

Currently they are still arguing over the need to use the NEC or to just write their own codes or to leave it as it has been for twenty years plus... but the fire department is asking them to do something and no one has any great idea because of electricity thefts and such. Fire department says putting it at certain height is within reach of the pole carried on fire truck, so the fire department could flip it off yet your normal burglar etc would need ladders to reach it. Current argument is not just an is it needed but how does the average person in the island who already is having trouble with new rules and costs of importing supplies afford something that costs so much when they have never needed it before.
But, this is a bunch of politicians arguing over wether or not there is a need for taxicabs to pay for their permits or have they been charged improperly..lol
A group of us who actually want to make sane safe rules for the industr are trying to find efficient ways to do this and find wether or not it is acceptable... under the codes most likely to be adopted and upgraded on a regular basis.
Since it has shown up in arguments in the USA, especially concerning solar installations, a few of us are trying to understand how the switches would relate to the feeder and service feeder rules, and also trying to find other ideas out, such as:
Would it be better to require installations to include the switch based upon the maximum allowable bus panel installed in the residence or based upon the service applied for when applying to the POCO.. so far all of us are in agreement that even if a person only applies for a 60 amp electricity service, if the panels installed are up to 125 amp, then this disconnect must be capable of the same 125 amp, and if the panels are 200 amp capable, then the switch must be 200 amp capable... a 60 amp switch should not be installed. But, are we right to require such a disconnect switch if installed to be bigger than the main OCPD?
In our groups mind, one of the most common reasons for electrical fires is overloading of services as installed so making the fireman switch be a minimum size of the maximum OCPD that can be installed in the panel boards just makes more sense than having a 60 amp switch on the outside of the home, the owner adds an AC unit and changes the main breaker to 90 or 100 amps because the panel can handle 125 amp breakers... but switch is incorrect. We had even considered asking the government to require the service cables from the meters to be set for the maximum bus rating regardless of the main OCPD. But that is recieving a lot of flak concerning costs, etc.
Our groups position is that you size feeders from one panel to another based on breaker at second panel but, hwo do you make sure there is enough main entrance cable?
Of course, the the arguments come in about well, it was sized for the needs, and if the need is now greater then we should replace the cables anyway...

[Craigv]

Most meter sockets have bypass capability, either horn, block, or lever, so I don't think it's a load interrupting issue. I think they just want to be able to kill power to the meter socket.

They can do as they please up to the service point. But there's a lack of logic to them wanting to shut off power to the last two feet of their system...they pretty much work live everywhere else. But again, their circus, their monkeys....

[Craigv]

Currently they are still arguing over the need to use the NEC or to just write their own codes or to leave it as it has been for twenty years plus... but the fire department is asking them to do something and no one has any great idea because of electricity thefts and such. Fire department says putting it at certain height is within reach of the pole carried on fire truck, so the fire department could flip it off yet your normal burglar etc would need ladders to reach it. Current argument is not just an is it needed but how does the average person in the island who already is having trouble with new rules and costs of importing supplies afford something that costs so much when they have never needed it before.
But, this is a bunch of politicians arguing over wether or not there is a need for taxicabs to pay for their permits or have they been charged improperly..lol
A group of us who actually want to make sane safe rules for the industr are trying to find efficient ways to do this and find wether or not it is acceptable... under the codes most likely to be adopted and upgraded on a regular basis.
Since it has shown up in arguments in the USA, especially concerning solar installations, a few of us are trying to understand how the switches would relate to the feeder and service feeder rules, and also trying to find other ideas out, such as:
Would it be better to require installations to include the switch based upon the maximum allowable bus panel installed in the residence or based upon the service applied for when applying to the POCO.. so far all of us are in agreement that even if a person only applies for a 60 amp electricity service, if the panels installed are up to 125 amp, then this disconnect must be capable of the same 125 amp, and if the panels are 200 amp capable, then the switch must be 200 amp capable... a 60 amp switch should not be installed. But, are we right to require such a disconnect switch if installed to be bigger than the main OCPD?
In our groups mind, one of the most common reasons for electrical fires is overloading of services as installed so making the fireman switch be a minimum size of the maximum OCPD that can be installed in the panel boards just makes more sense than having a 60 amp switch on the outside of the home, the owner adds an AC unit and changes the main breaker to 90 or 100 amps because the panel can handle 125 amp breakers... but switch is incorrect. We had even considered asking the government to require the service cables from the meters to be set for the maximum bus rating regardless of the main OCPD. But that is recieving a lot of flak concerning costs, etc.
Our groups position is that you size feeders from one panel to another based on breaker at second panel but, hwo do you make sure there is enough main entrance cable?
Of course, the the arguments come in about well, it was sized for the needs, and if the need is now greater then we should replace the cables anyway...

Wow. Sounds like analysis paralysis. NEC is a model code, it's flawed and certainly not written in stone. Use it and if needed modify whatever doesn't work in your situation.

Undersizing any component below the maximum load is foolish on the service side. The cost differences shouldn't be all that dramatic considering if the customer can afford the power bill and the goodies that consume it, they should be able to afford the gear to make it happen. Before the meter is usually before the service point, and undersized cable there really isn't the problem you might assume. It certainly isn't going to start a house on fire.

[jap]

Most meter sockets have bypass capability, either horn, block, or lever, so I don't think it's a load interrupting issue. I think they just want to be able to kill power to the meter socket.

Exactly.

JAP>