60A BRKR FEEDING A NEW 100A MLO PANEL

[Alwayslearningelec]

The panel with the 60a brkr is a 100a MLO, 208v 3p, 4w and the new panel is 100a MLO, 3P 4W. Can a 60a brkr feed a 100a panel.:?

The feeder would have to be rated for 60amps, correct? What code section can I find out more about this calculation? Thanks

 

[kwired]

The panel with the 60a brkr is a 100a MLO, 208v 3p, 4w and the new panel is 100a MLO, 3P 4W. Can a 60a brkr feed a 100a panel.:?

The feeder would have to be rated for 60amps, correct? What code section can I find out more about this calculation? Thanks

There is no code prohibiting this, as long as calculated load is not more than the 60 amp conductors and 60 amp protection.

You could feed 2000 amp equipment with a 60 amp circuit if you wish if there is only 60 amp of load. It is probably never done other than possibly for temporary purposes.

 

[Alwayslearningelec]

There is no code prohibiting this, as long as calculated load is not more than the 60 amp conductors and 60 amp protection.

You could feed 2000 amp equipment with a 60 amp circuit if you wish if there is only 60 amp of load. It is probably never done other than possibly for temporary purposes.

Thanks KWIRED....so the conductors need to be rated for 60a? Thanks.

 

[kwired]

Thanks KWIRED....so the conductors need to be rated for 60a? Thanks.

In general, if the overcurrent device is 60 amps - yes. If this is supplying a motor(s) or select other equipment that may have a high starting current there could be exceptions to allow for starting.

 

[jumper]

Thanks KWIRED....so the conductors need to be rated for 60a? Thanks.

Yes. As stated, as long as the load is 60A or less, the feeder, panel, and feeder/panel OCPD need only be rated at 60A minimum.

Here are the applicable NEC sections.

215.2 Minimum Rating and Size.
(A) Feeders Not More Than 600 Volts.
(1) General. Feeder conductors shall have an ampacity not
less than required to supply the load as calculated in Parts
III, IV, and V of Article 220. The minimum feeder-circuit
conductor size, before the application of any adjustment or
correction factors, shall have an allowable ampacity not
less than the noncontinuous load plus 125 percent of the
continuous load.

215.3 Overcurrent Protection. Feeders shall be protected
against overcurrent in accordance with the provisions of
Part I of Article 240. Where a feeder supplies continuous
loads or any combination of continuous and noncontinuous
loads, the rating of the overcurrent device shall not be less
than the noncontinuous load plus 125 percent of the continuous
load.

220.40 General. The calculated load of a feeder or service
shall not be less than the sum of the loads on the branch
circuits supplied, as determined by Part II of this article,
after any applicable demand factors permitted by Part III or
IV or required by Part V have been applied.

408.30 General. All panelboards shall have a rating not
less than the minimum feeder capacity required for the load
calculated in accordance with Part III, IV, or V of Article
220, as applicable.


408.36 Overcurrent Protection. In addition to the requirement
of 408.30, a panelboard shall be protected by an
overcurrent protective device having a rating not greater
than that of the panelboard. This overcurrent protective device
shall be located within or at any point on the supply
side of the panelboard.

 

[Alwayslearningelec]

So how is the load figured for that panel the 60a brkr is feeding if there are several branch circuits part of that panel?

Yes. As stated, as long as the load is 60A or less, the feeder, panel, and feeder/panel OCPD need only be rated at 60A minimum.

Here are the applicable NEC sections.

215.2 Minimum Rating and Size.
(A) Feeders Not More Than 600 Volts.
(1) General. Feeder conductors shall have an ampacity not
less than required to supply the load as calculated in Parts
III, IV, and V of Article 220. The minimum feeder-circuit
conductor size, before the application of any adjustment or
correction factors, shall have an allowable ampacity not
less than the noncontinuous load plus 125 percent of the
continuous load.

215.3 Overcurrent Protection. Feeders shall be protected
against overcurrent in accordance with the provisions of
Part I of Article 240. Where a feeder supplies continuous
loads or any combination of continuous and noncontinuous
loads, the rating of the overcurrent device shall not be less
than the noncontinuous load plus 125 percent of the continuous
load.

220.40 General. The calculated load of a feeder or service
shall not be less than the sum of the loads on the branch
circuits supplied, as determined by Part II of this article,
after any applicable demand factors permitted by Part III or
IV or required by Part V have been applied.

408.30 General. All panelboards shall have a rating not
less than the minimum feeder capacity required for the load
calculated in accordance with Part III, IV, or V of Article
220, as applicable.


408.36 Overcurrent Protection. In addition to the requirement
of 408.30, a panelboard shall be protected by an
overcurrent protective device having a rating not greater
than that of the panelboard. This overcurrent protective device
shall be located within or at any point on the supply
side of the panelboard.

 

[jumper]

So how is the load figured for that panel the 60a brkr is feeding if there are several branch circuits part of that panel?

kVA per circuit, balanced across phases or legs.