service disconnect

[vango]

VI. Service Equipment ?Disconnecting Means:
Article 230.70 (A)(1) (1) Readily Accessible Location. The service disconnecting
means shall be installed at a readily accessible location either outside of a building or structure or inside nearest the point of
entrance of the service conductors.
Then we have:
VII. Service Equipment ?Overcurrent Protection:
230.91 Location
The service overcurrent device shall be an integral part of the
service disconnecting means or shall be located immediately
adjacent thereto.

Somebody separate these two articles and their uses for me. Examples would be helpful.
Are disconnecting means and overcurrent protection not synonymous?
What I'm looking for is where can I put my main disconnect? "Nearest point of entry" has been the rule of thumb, not necessarily "adjacent thereto".

 

[Dennis Alwon]

Think of a manual transfer switch that has an off position but it isn't service rated. That means that overcurrent protective device is necessary either adjacent to that or immediately inside the building.

 

[Smart $]

...
Are disconnecting means and overcurrent protection not synonymous?
What I'm looking for is where can I put my main disconnect? "Nearest point of entry" has been the rule of thumb, not necessarily "adjacent thereto".

No, they are not synonymous... but often considered one and the same because of the "integral or immediately adjacent thereto" requirement for OCP.

"Nearest point of entry" is the requirement for the service disconnecting means (SDM), i.e. the service switch, only when installed inside. The OCPD, if not integral with the SDM, must be immediately adjacent thereto, which means, essentially, it must abut the SDM. You cannot install the SDM on one side of a wall and the OCPD on the other side.

 

[iwire]

Over current protection and disconnecting means are not synonymous.

A non-fused disconnect is an example of a disconnecting means that is not over current protection.

 

[GoldDigger]

The close association between the disconnect function and the overcurrent protection function is specific to the service disconnect. In that specific case either the OCPD must be integral with the disconnect (Breaker or fused disconnect) or the OCPD must be "immediately adjacent thereto".

Other disconnects may or may not be fused and do not require adjacent OCPD if they are not fused. In a typical circuit, however, there has to be branch or feeder OCPD but it does not have to be associated in any way with a disconnect.
A fused disconnect makes it easier to change fuses, since it provides a very local way to deenergize the fuses.

 

[vango]

Is the Main OCPD required to be "adjacent thereto" the utilities meterbase?

 

[GoldDigger]

Is the Main OCPD required to be "adjacent thereto" the utilities meterbase?

No, not unless it is part of a meter/main combo.

The meter could even be at a pedestal at the property edge and the service disconnect hundreds of feet away at the building.
The service point determines where the POCO wires end and the customer's service conductors begin. But both are "service" up to the disconnect and OCPD. The NEC does not call it out specifically, but I would say that the service wires end at the OCPD rather than the disconnect if they are not one and the same.

 

[kwired]

Is the Main OCPD required to be "adjacent thereto" the utilities meterbase?

It has been said on this site before and I will repeat it - to the NEC a meter base is nothing more then a "wide point" in the conductors in which a measuring device can be inserted. It can be before or after the service disconnect as well as before or after the service overcurrent protection. If after it can have a feeder/branch circuit disconnecting means/overcurrent protection before or after it.

Design specifications can make for easier maintenance or other operations by selecting specific placement of switches and overcurrent devices in relation to said meter, but some requirements you run into are only triggered by other design criteria - example if the meter is load side of the service disconnect you may no longer be able to bond the grounded conductor to the meter can (not going to dwell on any exceptions here), but that rule is triggered because you are on the load side of the service disconnect not because there has to be a service disconnect.

POCO's sometimes can set rules here as well, and because an option is used it may kick in other requirements like non fused disconnects before meters for the purpose of servicing the meter. NEC doesn't require them - but if they are used there are a few rules that possibly kick in that are not there if the disconnect is not there.