LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
Are you suggesting making each panel 120v only???
residential service wire size
- Thread starter melissa
- Start date
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kwired
Electron manager
- Location
- NE Nebraska
If the existing service is 120/240 3-wire then you may still be able to use the existing service to feed the two panels. If the panels both have 120 Volt loads you could balance the panels. One ungrounded conductor and common neutral would feed one of the 200 A panels and the other ungrounded conductor and common neutral would feed the other 200 A panel. The existing service would have a 200 A main circuit breaker but each panel would still be able to take 200 A simultaneously when balanced. If one panel CB is open then all 200 A would flow through the neutral instead.
If so you gained no additional capacity total VA between the two is still the same as total VA if a 120/240 volt panel is served.
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
Okay, but no 240v loads can be served.
mcclary's electrical
Senior Member
- Location
- VA
erickench
Senior Member
- Location
- Brooklyn, NY
Yes no 240 volt loads could be served unless you install a third panel to be your main panel. A small one that does'nt have that many circuit breakers is preferable. You can feed the two 200 A panels off this main panel along with any additional 240 volt loads. But what is the rating of the existing service disconnect?
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Was this determined per Article 220 Part II and III or IV?
Or is it just that all the breaker spaces in the existing panel are used?
Has an Article 220 Service calculation been performed, and if so, what is the required minimum VA determined by the calculation? If not, how do you even know whether a 400A service is required?
It is understood that a 440A service may be desired to allow for future growth if not required for current plans, but the only way to determine what is required for current plans and what is available for future growth is to do a service calculation.
Both or each?
Does this mean 80 feet away from the building?
Where is the current service disconnect located? Next to meter or the existing panel MCB, for example.
What is the planned service disconnect configuration and location?
Ask him if he's ever connected two services to one transformer (he likely has). If he admits to it, ask him how connecting parallel service conductors is any different.
Has a Certificate of Occupancy been issued? Will there be? That will tell you what the occupancy is considered.
Does anyone dwell there, such as the pastor, deacon, etc.? Could be a dual occupancy building. Only the local administration can answer this Q for certain.
kwired
Electron manager
- Location
- NE Nebraska
If more service capacity is needed you gained nothing except circuit breaker spaces. You would have been better off feeding a sub panel from the original. To get more service capacity you still need increases in the service conductors or an increase in voltage and a transformer to step voltage back down. The latter is probably not the most economical solution in most cases.
I'm not so sure that you would'nt want a panel with 200% neutral like they sometimes use for high harmonics since you will be carrying all 200 amps on the neutral if loaded that much. I don't know what the neutral assemblies on average 200 amp panel are designed for but I don't think I would trust them to carry that kind of load for long periods of time. They were likely intended to carry unbalanced phase current.
Voltage drop becomes a bigger issue with a panel that is supplied by 120 volt only. Maybe not for individual branch circuits but it does on the panel feeder. MWBC's are not possible.
erickench
Senior Member
- Location
- Brooklyn, NY
I don't think it would be a 200% neutral. Both panels would have a common neutral yes but if both are operating at full load the current would flow from one panel to the other with neutral having zero current. If one panel is operating at zero load then the neutral would have 100% current which in this case would be 200 A. Each panel would be rated at 120 Volts and the neutral would prevent a voltage imbalance.
If the existing service is 120/240 3-wire then you may still be able to use the existing service to feed the two panels. If the panels both have 120 Volt loads you could balance the panels. One ungrounded conductor and common neutral would feed one of the 200 A panels and the other ungrounded conductor and common neutral would feed the other 200 A panel. The existing service would have a 200 A main circuit breaker but each panel would still be able to take 200 A simultaneously when balanced. If one panel CB is open then all 200 A would flow through the neutral instead.
eric,
This is the most insane answer I have ever read, why would you suggest this to anyone?
If this is too blunt I am sorry, I just can't beleive what I'm seeing.
erickench
Senior Member
- Location
- Brooklyn, NY
Okay no common neutral. One neutral for each panel.:roll:
kwired
Electron manager
- Location
- NE Nebraska
I kind of feel the same way, was just waiting for some one else to chime in.
Throwing out codes there is still more disadvantages then there are advantages.
If more VA are what is needed it does not accomplish this at all - the conductors supplying all of this have not changed at all.
If more VA are not needed the OP just needs to sub feed another panel from the existing (in a traditional manner) and you have accomplished the same thing and or better.
My advice is if this is non-profit and you are donating your time is to run, very, very fast.. These guys are really sharp. You just need to start at the begining with loads and square footage along with what type of service you are going to have. IE: 1 phase 120/240, 3 phase 120/208. Then go from there.
erickench
Senior Member
- Location
- Brooklyn, NY
Okay the existing service will give you 200x240=48000VA. According to NEC Table 220.12 the VA per sq-ft for a Church is 1. But that's just for the lighting load. What is the square footage of the church?
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