Protection of service cable and bus in MLO cases

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Electriman

Senior Member
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TX
Greetings,

I was wondering when there is no service disconnect and the service cable terminates in MLO panel or switchgear what is going to protect the the bus bar of the panel or gear.
I was also wondering how the service cable is protected. Is there a fuse or breaker on the utility side that protect the cable and the bus? If our service panel is inside the building do we need the cable and conduit outside so we can comply with tap requirement?
 
Service conductors (which includes the bus bars of an MLO panel where the branch/feeder breakers form the service disconnect) are not limited by the tap rules.

And they are no more protected than the POCO service wires themselves. Hopefully something on the pole or in the drop will burn out before the bus bars, but if they do burn out the resulting fire should be limited because the service disconnect is outside the building or as close as practical to the entry point.
 
GoldDigger said:
Service conductors (which includes the bus bars of an MLO panel where the branch/feeder breakers form the service disconnect) are not limited by the tap rules.

And they are no more protected than the POCO service wires themselves. Hopefully something on the pole or in the drop will burn out before the bus bars, but if they do burn out the resulting fire should be limited because the service disconnect is outside the building or as close as practical to the entry point.
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What if the service panel is located inside building?
 
GoldDigger said:
Then it melts inside the building.
That is something that needs to be considered during the overall design process. It should not be far inside, nor should it be in a public area.

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Does NEC prohibits to install service panel inside building especially when it is MLO?
 
Electriman said:
Does NEC prohibits to install service panel inside building especially when it is MLO?
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No, but individual AHJs may either prohibit (via local amendments) or restrict so tightly as to make impractical (via interpretation of the NEC language "as close as practical".)

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