Panel

[Helpmeplease]

I have a 225amp MCB. panel. I am going to add at least 10-3pole 30 amp breakers and 10-1pole 20 amp breakers. The load is continuous. How do I calculate to see if this is too much load?

FYI its for a data center.

 

[iwire]

I have a 225amp MCB. panel. I am going to add at least 10-3pole 30 amp breakers and 10-1pole 20 amp breakers. The load is continuous. How do I calculate to see if this is too much load?

FYI its for a data center.

The numbers on the breaker handles are meaningless for this.

You need a list of all the loads you are connecting.

Can I assume this a is a three phase 208 volt panelboard?

 

[Helpmeplease]

The numbers on the breaker handles are meaningless for this.

You need a list of all the loads you are connecting.

Can I assume this a is a three phase 208 volt panelboard?

I do not know the specs on the loads. I know its computers equip. Yes its is a 3 phase 208v panel board.

 

[Sahib]

I have a 225amp MCB. panel. I am going to add at least 10-3pole 30 amp breakers and 10-1pole 20 amp breakers. The load is continuous. How do I calculate to see if this is too much load?

FYI its for a data center.

If breakers are continuous rated, load+25% may equal breaker rating. In that case, maximum load on one phase= (10*30)+(10*20)=500A. The 225A breaker would trip.
If the breaker is 80% rated, maximum load is limited to 500*0.8=400A. The 225A breaker would still trip.

 

[iwire]

I do not know the specs on the loads.

That is a real problem.

Without knowing the actual load you cannot tell if it will be too much for the panelbaord.

 

[ActionDave]

If breakers are continuous rated, load+25% may equal breaker rating. In that case, maximum load on one phase= (10*30)+(10*20)=500A. The 225A breaker would trip.
If the breaker is 80% rated, maximum load is limited to 500*0.8=400A. The 225A breaker would still trip.

So you are saying that a 500A load will trip a 225A breaker and even if you reduce the load to 400A it will still trip? What a piece of junk.

 

[kwired]

So you are saying that a 500A load will trip a 225A breaker and even if you reduce the load to 400A it will still trip? What a piece of junk.

I agree, plus 600 amp equipment is just too expensive to use in such an incident

 

[mwm1752]

I have a 225amp MCB. panel. I am going to add at least 10-3pole 30 amp breakers and 10-1pole 20 amp breakers. The load is continuous. How do I calculate to see if this is too much load?

FYI its for a data center.

for exact calculations - Each branch circuit supplys a load -- you have at least 20 loads to specify -- Loads that draw current for a time period of min 3hours are considered continuous -- for each of the continuous load multiply by 125% -- add all continuous loads & non continuous loads together --- KW/ (E x 1.72) = I - 3 phase --- under 225 ur good -- you said add so do the same for existing loads if they exist, include in calculations. 400 amps is quite a load of ----

Code lets you figure loads for feeders & services in the NEC articles -- follow the code sections

 

[Haji]

So you are saying that a 500A load will trip a 225A breaker and even if you reduce the load to 400A it will still trip? What a piece of junk.

Unless diversity factor taken into account. You did not figure it out?:dunce:

 

[augie47]

Real world analogy, take a look at your house panel. Add up the all the breaker ratings and you will get a number 2 to 3 times greater than the panel rating.
As other have stated you must have the actual loads and the diversity to come close. A lot of IT rooms I see will have a ton of 20 amp circuits with less than 5 amps on each.