Electrical Loading

Given the absolute lack of detail in your posting, the only possible answer is 3MVA.

There are many many factors that determine the proper answer. Without real data... any answer, including mine, is of no value.

You want an answer that is of some value? Then provide us with the data to work with.

I presently have a 2MVA service that services a company, I am looking at the possibility of upgrading the electrical service to supplort the addition of a new commercial web press. We are on a distribution loop from hydro and they have told me that they are only able to upgrade me to 3MVA as that is the capacity available to them at this time. I need with the new equipment around 3MVA they would swap out three 666 KVA and put in 3 x 1000 my switch is rated to 3000 amps and Eaton has told me that they think that I could run this at 100% capacity what I need to know is what is the opinion that hydro would allow me to load up my service to 100% of the rated capacity. If not they would take a extended time to run a new trunk to the company and I may miss the window to upgrade my equipment. I will retain the services of a engineer to confirm the rated loads but if this is a no go with hydro I would hate to waste these funds if I have no chance of getting approval. I can not seem to get a straight answer from hydro as to what limits they place on the design capacity of system.

Does this help ?

Yes, and it would have done earler if that information was in the original post.

There are essentially four issues here...

1) The size of your current service.

2) The anticipated new total demand from your facility after the proposed expansion.

3) The current capacity in the feeders from the utility into your facility.

4) What the utility can upgrade your feeders to.

The reason you can not get a straight answer from the utility on how high you may load a given service is because it is not up to them to make that determination. They will provide feeders into a facility with a contracted capacity, how you control and distribute that power is up to you and your engineers.

The rest of my comments will be based on a Canadian perspective. In Canada it is not up to the utility to determine the maximum loading on a consumer service. The maximum loading on this type of gear is mandated by the rules found in the CEC.

Pieces of switch gear have ratings marked on them that indicate maximum loading for that particular piece of equipment. It will either be rated for 80% or 100% continuous operation at marked ampacity, or have no marking at all.

After the maximum rating of the gear is figured out, the maximum loading in the circuits downstream from the gear is determined by the nature of the conductors connected to the gear.

Using the term "around 3MVA" with the utility, it is no surprise they are hesitant to comment further.

For what it is worth... you need to hire a competent EE who will do a full blown survey of your existing system, if that data is not handy. He will do a proper demand load calculation on what your existing facility needs, plus your new anticipated demand from the new equipment and... he will factor in an amount for future load growth.

The result of this will also be a clear path on what needs to be done to your distribution system to handle the load patterns anticipated, which is an important piece of the puzzle.

This will allow you to come to a demand figure that you can take to the utility for their comment and either a commitment from them that they can supply your needs or their course of action to meet your need.

Finaly... you always approach these things from the perspective of what you need first of all. Then determine how to provide it. You do not provide it and then hope it is enough.

Thank you for your comments, I have retained a EE to do a load study for us

Regards