# Is this panel overloaded?

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#### qcroanoke

##### Sometimes I don't know if I'm the boxer or the bag
200 amp main breaker with a calculated load of 179 amps.
Is this overloaded?
Thanks!

#### jumper

##### Senior Member
Assuming the calculated load = 100% of the non-continuous load + 125% of the continuous load, I would say no.

#### iwire

##### Moderator
Staff member
Assuming the calculated load = 100% of the non-continuous load + 125% of the continuous load, I would say no.
I agree, under those conditions a 200 amp panel can handle a calculted load of 200 amps.

#### david luchini

##### Moderator
Staff member
I'd say its impossible to know if the panel is overloaded without knowing how much of the load is continuous and how much is non-continuous.

If the load is calculated per 220.40, by the sum of the loads on the branch circuits supplied as determined by Part II of article 220, then the load is 100% of the continuous plus 100% of the non-continuous. You need to know how much is continuous/non-continuous to ensure compliance with 215.3.

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#### Little Bill

##### Moderator
Staff member
200 amp main breaker with a calculated load of 179 amps.
Is this overloaded?
Thanks!
Not unless those are really heavy amps!:lol:

#### Cow

##### Senior Member
200 amp main breaker with a calculated load of 179 amps.
Is this overloaded?
Thanks!
Wouldn't it be overloaded only if it was carrying more than 200 amps??

#### Smart \$

##### Esteemed Member
Wouldn't it be overloaded only if it was carrying more than 200 amps??
It could be overloaded if it were carrying 161A and all the loads were continuous...

#### Cow

##### Senior Member
It could be overloaded if it were carrying 161A and all the loads were continuous...
That wouldn't be the calculated load then, would it?

#### Smart \$

##### Esteemed Member
That wouldn't be the calculated load then, would it?
No. I intentionally made certain I did not say it was, and only that it "could be" overloaded.

#### david luchini

##### Moderator
Staff member
That wouldn't be the calculated load then, would it?
The calculated load could be all continuous, or all non-continuous, or some combination thereof. If the calculated load is 100kVA;

That could be 50kVA continuous and 50kVA non-continuous, or...
That could be 10kVA continuous and 90kVA non-continuous, or...
That could be 87.5kVA continuous and 12.5kVA non-continuous...

I think there is a misconception that if you have a load that is 50kVA continuous and 50kVA non-continuous, then the "calculated load" is 112.5kVA. I don't think you'll find anything in 220.40 that says the calculated load is 100% of the non-continuous plus 125% of the continuous load. The 125% of continuous load is found in Article 215 relating to the sizing of the feeder conductors and OCP for the feeder.

Take a look at example D3 in the appendix. It show a non-continuous load of 12.2kVA, a continuous load of 16.2kVA, and a total load of 28.4kVA (not a total load of 32.75kVA.)

#### Smart \$

##### Esteemed Member
The calculated load could be all continuous, or all non-continuous, or some combination thereof. If the calculated load is 100kVA;

That could be 50kVA continuous and 50kVA non-continuous, or...
That could be 10kVA continuous and 90kVA non-continuous, or...
That could be 87.5kVA continuous and 12.5kVA non-continuous...

I think there is a misconception that if you have a load that is 50kVA continuous and 50kVA non-continuous, then the "calculated load" is 112.5kVA. I don't think you'll find anything in 220.40 that says the calculated load is 100% of the non-continuous plus 125% of the continuous load. The 125% of continuous load is found in Article 215 relating to the sizing of the feeder conductors and OCP for the feeder.

Take a look at example D3 in the appendix. It show a non-continuous load of 12.2kVA, a continuous load of 16.2kVA, and a total load of 28.4kVA (not a total load of 32.75kVA.)
True....

...but then there is this regarding panelboards:

408.30 General. All panelboards shall have a rating not
less than the minimum feeder capacity required for the load
calculated in accordance with Parts II, III, IV, or V of Article
220 as applicable.
So panels must also be rated not less than 125% of the continuous plus 100% of the non-continuous loads that it supplies.

#### Smart \$

##### Esteemed Member
It could be overloaded if it were carrying 161A and all the loads were continuous...
That wouldn't be the calculated load then, would it?
No. I intentionally made certain I did not say it was, and only that it "could be" overloaded.
So here's the real question...

If a 200A panel is supplying over 200A of current for more than 3 hours (without tripping the main), per the NEC, is it overloaded for certain, not overloaded for certain, or perhaps overloaded but not necessarily?

#### iwire

##### Moderator
Staff member
Unreal ..........

#### sameguy

##### Senior Member
Are you out of money or do you still have checks?
How was the load calc. made?

#### david luchini

##### Moderator
Staff member
So panels must also be rated not less than 125% of the continuous plus 100% of the non-continuous loads that it supplies.
Yes...that's why it is impossible to know if the panel is overloaded given the information in the OP. You must know how much of the load is continuous and how much is non-continuous.

#### infinity

##### Moderator
Staff member
Yes...that's why it is impossible to know if the panel is overloaded given the information in the OP. You must know how much of the load is continuous and how much is non-continuous.
The OP did say "200 amp main breaker with a calculated load of 179 amps". Why assume that there's a problem with the calculation? Don't the words calculated load imply that both continuos and non-continuos loads have been considered or are we working from a new definition in this thread?

#### kingpb

##### Senior Member
200 amp main breaker with a calculated load of 179 amps.
Is this overloaded?
Thanks!
Based on the question as stated, the equipment is not overloaded, however it may be undersized, per sizing requirements of the NEC.

#### infinity

##### Moderator
Staff member
Based on the question as stated, the equipment is not overloaded, however it may be undersized, per sizing requirements of the NEC.

Why?

#### kingpb

##### Senior Member
Don't confuse, "may" (possibility exists) with "is". It may or may not be undersized depending on the mix of continuous and non-continuous loads.

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