100 amp main 100amp disconect
- Thread starter herrera
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petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- engineer
You need to do a load calculation in accordance with article 220.
That will tell you what size service you need.
Don't be too surprised if the POCO does not change their wiring or xfmr.
You might end up just adding another 100A panel and using the same utility conductors to feed both.
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
Though upgrade may still be wise, x-ray machine probably has a high inrush current, and a duration of just milliseconds and then sits nearly idle again until next exposure. I bet it wouldn't cause too much trouble with what is existing other then possibly voltage sags when an exposure does occur. Duration is not long enough to trip the main unless existing loads are already pushing it up far enough to get into instantaneous trip ranges when an image is taken.
May also want to check with x-ray equipment supplier and any issues they may have with voltage drop/stability, that alone may be a big reason to update the main supply even if it could handle it otherwise. Don't maintain their specs for voltage drop and they may not warranty anything.
May also want to check with x-ray equipment supplier and any issues they may have with voltage drop/stability, that alone may be a big reason to update the main supply even if it could handle it otherwise. Don't maintain their specs for voltage drop and they may not warranty anything.
petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- engineer
getting the POCO to change their wiring and xfmr might be the issue though.
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
They will do it, but may be a price for it, also may not be any guarantee how soon they will do it with some places. Most around here want to meet customer needs, and feel they are there to serve those customers. I understand from what some post on here that the POCO's in some areas are more concerned about lining investor's pockets, then customer service.
petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- engineer
Since most POCOs these days are highly regulated and are actually required to charge customers for services they require, I think it is moderately unfair to suggest they are only interested in a profit. The POCO that hooks you up to the supply of electricity typically does not actually sell you any electricity. They are only in the distribution business. What could possibly make you think that it is fair to make other people pay for the costs of upgrading your service? it is not about "customer service" at all. It is about fairness to all the customers. If you as a customer add cost, you should pay for it, not the other customers.
meternerd
Senior Member
- Location
- Athol, ID
- Occupation
- retired water & electric utility electrician, meter/relay tech
As a utility guy (former), I would guess the utility will give you whatever size service you want, and charge you accordingly for the upgrade. They would, of course, want to see an inspection tag from the AHJ before hooking it back up. Fair for everyone. How long it takes is a whole other issue.
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
We still have publicly owned electric utilities here, they don't provide as much for free as they used to, but that is to help keep cost down more so then they don't want to do those things they used to do for free. In general you still get more of a break on equipment costs though if you are a high usage customer then if you have same peak demand but not so high of usage. All these public utilities do sell the power they distribute, and we have some of the lowest rates in the nation, maybe not the lowest but in top ten from what I understand. Those privately owned POCO's need to pay their greedy owners and investors, our public power companies are customer owned and make little profit, what they do make is reinvested into the system not distributed to CEO's. I hope we keep them that way for a long time.
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