Calling all Electrical Engineers

[PinesAndProjectiles]

I’m installing a piece of equipment that has an FLA of 1200A. V is 480 and is three phase.

My switchgear is a Square D iLine 42.

Per Square D, the biggest breaker the gear can fit is a 600A.

It isn’t feasible to upgrade the gear at this time.

The switchgear currently has three breakers, each rated for 400A.

If I ran three feeders, one from each of the 400A breakers, could I feed the 1200A disconnect on the equipment without issue?

 

[DarnYankeeUSMC]

What is the minimum circuit amps for the machine?

 

[CxAgent]

Short answer is no. You can overload the 600 amp panel at full load. Also, what size breaker feeds the 600 amp panel. Most likely you would trip the upstream breaker. The other issue would be the AIC rating. A short in the machine could turn your panel into a 600 amp grenade.

 

[PinesAndProjectiles]

What is the minimum circuit amps for the machine?

Not sure but I’ll find out.

 

[PinesAndProjectiles]

Short answer is no. You can overload the 600 amp panel at full load. Also, what size breaker feeds the 600 amp panel. Most likely you would trip the upstream breaker. The other issue would be the AIC rating. A short in the machine could turn your panel into a 600 amp grenade.

The switchgear is rated for 4,000A.

I’m wanting to run off of three, 400A breakers being a 1,200A isn’t an option.

 

[Srgt. Hulka]

You should get the number off your meter, contact the power company, get your peak demand for the last year, and find out if you have enough capacity on your service to add that much load. Adding that much load at one time, I’ll bet you’ll be looking at needing a new service.
If you do have enough capacity, like others have said, you cannot feed it from the 600A panel. You’ll need to come from the 4000A switchgear.

 

[PinesAndProjectiles]

You should get the number off your meter, contact the power company, get your peak demand for the last year, and find out if you have enough capacity on your service to add that much load. Adding that much load at one time, I’ll bet you’ll be looking at needing a new service.
If you do have enough capacity, like others have said, you cannot feed it from the 600A panel. You’ll need to come from the 4000A switchgear.

The service is only a year old.

There are two, 600A breakers, and two, 150A breakers used, that is all.

I have three conduits in the floor from the 4k service to the equipment that needs 1200A.

 

[dustingaunder]

Check NEC 240.8.

 

[missed]

Short answer is no,

If the equipment you are supplying service to needs 1200A and you have 3 runs of 400A to it you still only have a 400A service to the equipment.

If the equipment you are supplying has a subpanel in it and you can section off the loads there that could be an option. I have had to do design work in the past for that.

I am not familiar with the i-line 42 off the top of my head, it may be possible to add another section of gear to house a 1200A breaker if the gear is rated for 4000A. Even if that is a 4000A switchgear the utility more than likely only set a transformer and pulled cable for what was on the original service request information which may not be enough for this new 1200A load.

What is the main breaker size ?

 

[Bullfrog08]

I’m installing a piece of equipment that has an FLA of 1200A. V is 480 and is three phase.

My switchgear is a Square D iLine 42.

Per Square D, the biggest breaker the gear can fit is a 600A.

It isn’t feasible to upgrade the gear at this time.

The switchgear currently has three breakers, each rated for 400A.

If I ran three feeders, one from each of the 400A breakers, could I feed the 1200A disconnect on the equipment without issue?

Look at NEC 240.8

 

[Threadcutter308]

The service is only a year old.

There are two, 600A breakers, and two, 150A breakers used, that is all.

I have three conduits in the floor from the 4k service to the equipment that needs 1200A.

What kind of equipment is this ? Seems logical that there's a very large motor (or multiples) involved. If so, the inrush current (upon start) is somewhere between six and eight times the continuous FLA rating. I doubt very much that the power company is going to allow you to even start that beast across the line. So, there would have to be either a Softstart or VFD involved.

Or, maybe it's just a big heater of some sort, I don't know, you haven't said.

The reason that manufacturers limit the maximum breaker size in their euipment is the maximum current rating/capability of the internal bussing. The bussing has finite limits in terms of current carrying capabilities.

1200 Amps is at the top end of what 480 Vac services usually provide. You are a long ways over the line in terms of needing a new service, it isn't even close. In that regard, the age of your existing service is not relevant.

I'd strongly suggest getting in touch with a reputable INDUSTRIAL Electrical Contractor, have them come in and quote you the proper equipment With installation. And no, it's not going to be cheap.

 

[PinesAndProjectiles]

Short answer is no,

If the equipment you are supplying service to needs 1200A and you have 3 runs of 400A to it you still only have a 400A service to the equipment.

If the equipment you are supplying has a subpanel in it and you can section off the loads there that could be an option. I have had to do design work in the past for that.

I am not familiar with the i-line 42 off the top of my head, it may be possible to add another section of gear to house a 1200A breaker if the gear is rated for 4000A. Even if that is a 4000A switchgear the utility more than likely only set a transformer and pulled cable for what was on the original service request information which may not be enough for this new 1200A load.

What is the main breaker size ?

There really isn’t provisions for a sub panel, but the equipment cabinet supplies power to six, 125HP motors.

I may be able to split it up so that I have one feed for each pair of 125HP motors.

 

[PinesAndProjectiles]

What kind of equipment is this ? Seems logical that there's a very large motor (or multiples) involved. If so, the inrush current (upon start) is somewhere between six and eight times the continuous FLA rating. I doubt very much that the power company is going to allow you to even start that beast across the line. So, there would have to be either a Softstart or VFD involved.

Or, maybe it's just a big heater of some sort, I don't know, you haven't said.

The reason that manufacturers limit the maximum breaker size in their euipment is the maximum current rating/capability of the internal bussing. The bussing has finite limits in terms of current carrying capabilities.

1200 Amps is at the top end of what 480 Vac services usually provide. You are a long ways over the line in terms of needing a new service, it isn't even close. In that regard, the age of your existing service is not relevant.

I'd strongly suggest getting in touch with a reputable INDUSTRIAL Electrical Contractor, have them come in and quote you the proper equipment With installation. And no, it's not going to be cheap.

Yes, six, 125 HP motors, all of which are on VFDs and all are programmed to start at separate times to decrease inrush current.

 

[missed]

What size main breaker is in the switchgear ?

You may have some options, having an electrical engineer and or industrial electrical contractor out would be the best path forward. Along with getting your utility company involved to ensure there is enough there to supply all this.
Splitting loads up in this equipment is going to require someone reviewing the control system also. For example if one 400A feeder tripped and shut down 2 of these motors how does it affect the rest of the machine ? I would expect the machine to have the single 1200A service going to it and breakers and or fuses to protect each motor/VFD, and breakers for each of the other machine loads. If this is a new machine, this could also void any factory support and or warranty doing anything past the customer connection points.

 

[Srgt. Hulka]

There really isn’t provisions for a sub panel, but the equipment cabinet supplies power to six, 125HP motors.

I may be able to split it up so that I have one feed for each pair of 125HP motors.

Is it a single piece of equipment?
Does it have a single point connection for the feeders?
If yes, all the controls are in the machine. Don't try to feed it with multiple circuits. Don't try to half-ass it. Do it right the first time. There are no shortcuts with stuff like this.

Look at the nameplate on the equipment. Post a picture here. The nameplate will tell you what you need. FLA, MCA, and MOCP.
Post pictures of all your switchgear, including the nameplates.

The service is only a year old.

There are two, 600A breakers, and two, 150A breakers used, that is all.

I have three conduits in the floor from the 4k service to the equipment that needs 1200A.

It sounds like you have provisions in place to feed this machine. The conduits from the switchgear should be a minimum of 3 1/2", hopefully 4".

 

[PinesAndProjectiles]

I’ve been in contact with Square D

Our only option is to add a cabinet of the 48 series iLine which is capable of housing a 1200 amp breaker.

 

[missed]

That will be part of the best way to do it.

Your utility provider may still shit all over you if that load isn't in the calculations. Transformer and feeder cables may not be sized for it.

Is there a 3200 or 4000A main breaker in that gear?

What is it?

 

[PinesAndProjectiles]

That will be part of the best way to do it.

Your utility provider may still shit all over you if that load isn't in the calculations. Transformer and feeder cables may not be sized for it.

Is there a 3200 or 4000A main breaker in that gear?

What is it?

That I don’t know.

 

[The D]

How can I be of service?

Edit: Sorry for the obviously unhelpful response. I’ve had a shitty few weeks and need a reason to make myself chuckle. Carry on

 

[PinesAndProjectiles]

How can I be of service?

View attachment 8158230


Edit: Sorry for the obviously unhelpful response. I’ve had a shitty few weeks and need a reason to make myself chuckle. Carry on

Apologizing for smart ass remarks in the pit?

You heathen!

 

[The D]

Apologizing for smart ass remarks in the pit?

You heathen!

Lol, silly me

 

[Faronth]

I presume you already know how long you are going to wait for new gear if you order it today?..
Unless you know the Electric Gear Fairy you are probably looking well into 2024.

 

[n2ishun]

It's like this man......

 

[PinesAndProjectiles]

I presume you already know how long you are going to wait for new gear if you order it today?..
Unless you know the Electric Gear Fairy you are probably looking well into 2024.

Yep. If I can get a breaker to fit the the gear, it’s 52 weeks. Minimum.

If I need new gear, it’s also 52 weeks. Minimum.

 

[missed]

You may be able to run down the custom switch gear companies and see if they can design and fab that section with a better lead time.

We needed a section for a 1970's era Westinghouse 4kV gear, which Eaton owns the design for now. During the plandemic they quoted us like 2 years and a custom shop ( may have been Powell ) was 3-6 months. Surplus may be another option.

 

[Faronth]

Yep. If I can get a breaker to fit the the gear, it’s 52 weeks. Minimum.

If I need new gear, it’s also 52 weeks. Minimum.

That's actually better then I figured. New service entrance gear for ground ups and the like is being quoted at 12 to 18 months for some of our projects.
Best of luck on resolving your project obstacles.