Feeder Taps Unlimited length

[onewireatatime]

Hello Everyone, I have this 400a Meter/Main Breaker Load center panel at the entrance of the property, That will be feeding 2 dwellings. The first dwelling will have a 100amp breaker coming out of this meter/main to feed dwelling #1. For dwelling #2 I will be installing Sub Feed lugs at this meter/main and feeding a 400amp panel roughly 1,100' direct burial down to a Main Lug Only 400a P1aL Panel, that will contain a 200a and a 100a branch circuits to feed dwelling #2 and a well pump. My question is, does the 400a P1al Main Lug panel have to have a main breaker or can I keep it as a Main lug Only. Does this install fall under the unlimited length feeder tap rule? which i believe it mentions i need to terminate to an OCPD. Thank you

 

[Dennis Alwon]

Sounds like you are tapping the service conductors or are you tapping after the 400 amp breaker?

 

[onewireatatime]

Sounds like you are tapping the service conductors or are you tapping after the 400 amp breaker?

I'm tapping after the 400amp breaker.

 

[texie]

I'm tapping after the 400amp breaker.

So this is an outside feeder tap fed from the fed through lugs. It needs to have an EGC run with it and have a single OCPD at the building end based on the ampacity of the tap conductors. But you still need to have a disconnect at each building. Also must have a GES at each building connected to the EGC and do not bond the neutral.

 

[onewireatatime]

Hello Everyone, I have this 400a Meter/Main Breaker Load center panel at the entrance of the property, That will be feeding 2 dwellings. The first dwelling will have a 100amp breaker coming out of this meter/main to feed dwelling #1. For dwelling #2 I will be installing Sub Feed lugs at this meter/main and feeding a 400amp panel roughly 1,100' direct burial down to a Main Lug Only 400a P1aL Panel, that will contain a 200a and a 100a branch circuits to feed dwelling #2 and a well pump. My question is, does the 400a P1al Main Lug panel have to have a main breaker or can I keep it as a Main lug Only. Does this install fall under the unlimited length feeder tap rule? which i believe it mentions i need to terminate to an OCPD. Thank you

This is a new construction project in a large open lot. Meter Main is located outside and all of its feeders will be ran underground to each dwelling.

 

[onewireatatime]

So this is an outside feeder tap fed from the fed through lugs. It needs to have an EGC run with it and have a single OCPD at the building end based on the ampacity of the tap conductors. But you still need to have a disconnect at each building. Also must have a GES at each building connected to the EGC and do not bond the neutral.

The first dwelling will have a 100a main breaker at main service breaker load center. The second dwelling will be coming out of the feed thru lugs from the main service breaker to a Main lug only panel at the 2nd dwelling. So what you are saying is that i need a main breaker at the second dwelling, not a MLO, which is fed from the feed thru lugs. Does this OCPD have to be before entering the building if its underground? Or can i install a main breaker panel inside and go straight to it.

 

[tortuga]

For dwelling #2 I will be installing Sub Feed lugs at this meter/main and feeding a 400amp panel roughly

Feeder to dwelling #2 is not a 'tap' its just a 400A feeder.
Disconnect at dwelling #2 is per 225.32 & 408.36.

1,100' direct burial down to a Main Lug Only 400a P1aL

1100 foot run ? is that a type'o? Whats the calculated load for dwelling #2? How many parallel sets and what size wire?

 

[onewireatatime]

Feeder to dwelling #2 is not a 'tap' its just a 400A feeder.
Disconnect at dwelling #2 is per 225.32 & 408.36.

1100 foot run ? is that a type'o? Whats the calculated load for dwelling #2? How many parallel sets and what size wire?

1,100' 2 parrallel sets of 750mcm. aluminum. Either USE-2 or URD 750 quadplex windham cable. Which brings up another question. URD cable is not listed by the NEC, can I still use this cable outside only? And transition before entering dwelling?

 

[onewireatatime]

1,100' 2 parrallel sets of 750mcm. aluminum. Either USE-2 or URD 750 quadplex windham cable. Which brings up another question. URD cable is not listed by the NEC, can I still use this cable outside only? And transition before entering dwelling?

As for dwelling #2 being fed by the 400a main panel feed thru lugs, I always taught that was to be treated as a tap.

 

[onewireatatime]

Feeder to dwelling #2 is not a 'tap' its just a 400A feeder.
Disconnect at dwelling #2 is per 225.32 & 408.36.

1100 foot run ? is that a type'o? Whats the calculated load for dwelling #2? How many parallel sets and what size wire?

Dwelling #2 calculated load of 250a

 

[texie]

As for dwelling #2 being fed by the 400a main panel feed thru lugs, I always taught that was to be treated as a tap.

If you run conductors with an ampacity of 400 it is just a feeder and you would just need a disconnect at the building end. The 2 breakers could serve that purpose in the MLO panel. If run conductors smaller than 400 amp then it is an outside tap and it will need to terminate at a single OCPD no larger than the ampacity of the conductors.

 

[Dennis Alwon]

It is a tap as you stated but the tap must end in an overcurrent protective device as stated. Depending on which code you are under changes whether the disconnect needs to be outside. 2020 demands them outside while before that the disconnect needed to be as near as possible to the point of entry.

 

[hornetd]

Under the 2020 NEC all panels must have a means of deenergizing the entire interior. There are exceptions but they don't apply in a presently available Meter Mains assembly. If you use feed through lugs to supply that remote panel at dwelling #2 you cannot use an MLO panel because the panel would be able to accommodate more than 6 building disconnecting means. If you substitute an enclosed breaker as the building disconnecting means and you mount it on the exterior of the building; or better still on a stanchion 25 feet away [although that last is certainly not a code requirement]; then you will be in compliance with the requirement for an exterior emergency disconnect. If you do use a stanchion to support your exterior disconnect you can also use it to support a separate enclosed breaker for the well pump.

Additional suggestion regarding fire protection! Unless this property is located within a couple of miles or a fire house which is staffed around the clock you may want to consider running separate supply conductors tapped directly off of the meter to the water well. That could be a separate switch or circuit breaker located adjacent to the meter mains or service conductors run to service equipment for the well power which is located elsewhere. That will assure that the pressurized water from the well will remain available for first aid fire suppression until the fire service arrives. Even if the fire has already caused the 400 ampere main breaker to open on a fault the water pump would still have power. The least cost way to provide separate power to the well would be to run 3 underground service entry conductors to a Service Disconnecting Means located at the well or quite close to it. That would save you the cost of a 4th conductor for the Equipment Grounding Conductor which would be required if it were a feeder. If it were a 240 volt branch circuit then you could run just three wires just like you could for a service. The only catch would be that all parts of the well equipment including it's controls would need to be 240 volt. I would use the service lateral approach so that I could use 120 volt loads such as a heater and a light in a well house.

If I could afford it I would put in an underground vault at the well to hold the pressure tanks and controls. If enough of the vault were below the frost line the vault would stay above freezing from just the ground temperature. For that to work at least 1/2 of the vault would have to be below the frost line and any portion above the frost line would have to be hyper insulated.

 

[onewireatatime]

Under the 2020 NEC all panels must have a means of deenergizing the entire interior. There are exceptions but they don't apply in a presently available Meter Mains assembly. If you use feed through lugs to supply that remote panel at dwelling #2 you cannot use an MLO panel because the panel would be able to accommodate more than 6 building disconnecting means. If you substitute an enclosed breaker as the building disconnecting means and you mount it on the exterior of the building; or better still on a stanchion 25 feet away [although that last is certainly not a code requirement]; then you will be in compliance with the requirement for an exterior emergency disconnect. If you do use a stanchion to support your exterior disconnect you can also use it to support a separate enclosed breaker for the well pump.

Additional suggestion regarding fire protection! Unless this property is located within a couple of miles or a fire house which is staffed around the clock you may want to consider running separate supply conductors tapped directly off of the meter to the water well. That could be a separate switch or circuit breaker located adjacent to the meter mains or service conductors run to service equipment for the well power which is located elsewhere. That will assure that the pressurized water from the well will remain available for first aid fire suppression until the fire service arrives. Even if the fire has already caused the 400 ampere main breaker to open on a fault the water pump would still have power. The least cost way to provide separate power to the well would be to run 3 underground service entry conductors to a Service Disconnecting Means located at the well or quite close to it. That would save you the cost of a 4th conductor for the Equipment Grounding Conductor which would be required if it were a feeder. If it were a 240 volt branch circuit then you could run just three wires just like you could for a service. The only catch would be that all parts of the well equipment including it's controls would need to be 240 volt. I would use the service lateral approach so that I could use 120 volt loads such as a heater and a light in a well house.

If I could afford it I would put in an underground vault at the well to hold the pressure tanks and controls. If enough of the vault were below the frost line the vault would stay above freezing from just the ground temperature. For that to work at least 1/2 of the vault would have to be below the frost line and any portion above the frost line would have to be hyper insulated.

Very informative, Thank You.

 

[texie]

Very informative, Thank You.

Under the 2020 NEC all panels must have a means of deenergizing the entire interior. There are exceptions but they don't apply in a presently available Meter Mains assembly. If you use feed through lugs to supply that remote panel at dwelling #2 you cannot use an MLO panel because the panel would be able to accommodate more than 6 building disconnecting means

This is simply not true. If the OP installs this as a full size feeder he can have 1 to 6 mains in a MLO panel at the building. If he installs reduced size conductors relative to the 400 amp main then it is an outside tap and will need a single OCPD at the building.

 

[kwired]

This is simply not true. If the OP installs this as a full size feeder he can have 1 to 6 mains in a MLO panel at the building. If he installs reduced size conductors relative to the 400 amp main then it is an outside tap and will need a single OCPD at the building.

I agree see 225.33.

Service disconnecting means is no longer allowed to be six disconnects in same enclosure. Feeder supplied buildings can still do that though - you still have the ability to disconnect at the feeder breaker where with services you often have no easy way to disconnect the supply without calling out the POCO.

 

[tortuga]

Additional suggestion regarding fire protection! Unless this property is located within a couple of miles or a fire house which is staffed around the clock you may want to consider running separate supply conductors tapped directly off of the meter to the water well. That could be a separate switch or circuit breaker located adjacent to the meter mains or service conductors run to service equipment for the well power which is located elsewhere. That will assure that the pressurized water from the well will remain available for first aid fire suppression until the fire service arrives. Even if the fire has already caused the 400 ampere main breaker to open on a fault the water pump would still have power. The least cost way to provide separate power to the well would be to run 3 underground service entry conductors to a Service Disconnecting Means located at the well or quite close to it. That would save you the cost of a 4th conductor for the Equipment Grounding Conductor which would be required if it were a feeder. If it were a 240 volt branch circuit then you could run just three wires just like you could for a service. The only catch would be that all parts of the well equipment including it's controls would need to be 240 volt. I would use the service lateral approach so that I could use 120 volt loads such as a heater and a light in a well house.

If I could afford it I would put in an underground vault at the well to hold the pressure tanks and controls. If enough of the vault were below the frost line the vault would stay above freezing from just the ground temperature. For that to work at least 1/2 of the vault would have to be below the frost line and any portion above the frost line would have to be hyper insulated.

Great advice right there.