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Main lug only breaker box with main breaker in its own enclosure?

Main lug only breaker box with main breaker in its own enclosure?

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Old 05-31-10, 08:51 AM
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Main lug only breaker box with main breaker in its own enclosure?

Trying to get a game plan together on a complete electrical re-do on our new project house ... Here's my question:

Can I have an enclosure for just the main breaker (positioned near the meter), feeding a main lug panel somewhere inside the house?


Thanks,

Edward
 
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Old 05-31-10, 08:56 AM
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Better would be to also include the reason you would like to to this.
 
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Old 05-31-10, 09:21 AM
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Yes, you can. The MLO panel becomes a subpanel and needs to be fed with a ground conductor separate from the neutral conductor. In this case, the ground conductors and neutral conductors of branch circuits must be kept seperated; a seperate ground bar is required. Do not bond the neutral bus to the panel can.
 
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Old 05-31-10, 11:42 AM
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I find often times the main breaker panels are less expensive than the MLO. These can still be installed after the service disconnect outside. The main breaker just beomes a redundant shutoff.

The 4 wire feeder mentioned above would still need to be run, along with the isolation of the neutrals and grounds.
 
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Old 05-31-10, 12:20 PM
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Awesome guys, thanks for the input.

My wife and I just bought a project house and the wiring needs some serious attention. The house was built in 1950 that has a detached guest house; both have their own meter on the back side of the main house where the service comes in.

Main house has 4 wire, 3 phase power (240V delta) and I want the panel located inside a utility closet in the interior of the house ... which is more than 10' away from the meter. I'm looking at the Square D NQOD panels, and the MLO units are a bit shorter and I had assumed (incorrectly?) they were less expensive than a main breaker panel - I'll have to check on that though.

Wife is getting anxious so I better get back to work ... I'll be back with more questions!


Thanks,

Edward
 
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Old 05-31-10, 12:42 PM
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Originally Posted by Eddiep View Post
Awesome guys, thanks for the input.

My wife and I just bought a project house and the wiring needs some serious attention. The house was built in 1950 that has a detached guest house; both have their own meter on the back side of the main house where the service comes in.

Main house has 4 wire, 3 phase power (240V delta) and I want the panel located inside a utility closet in the interior of the house ... which is more than 10' away from the meter. I'm looking at the Square D NQOD panels, and the MLO units are a bit shorter and I had assumed (incorrectly?) they were less expensive than a main breaker panel - I'll have to check on that though.

Wife is getting anxious so I better get back to work ... I'll be back with more questions!


Thanks,

Edward

Speaking of 3 phase delta system I know they used the delta system when they were used for central A/C unit and some case they used delta system to run the garage or workshop where you have a bit of three phase motours.

I want to give you a head up be extra carefull with delta leg aka Wild leg or other words that will result if you used the wild leg to netural the voltage will be 208 volts so if anything on 120 volts it will make a magic smoke real quick.

The other thing is with delta system the delta leg will have smaller phase conductor than other two { this is common used in older resdentail area }

The SqD NOQD panel is bolt on { but it can have push on capitcy as well} and it will cost some how more than just standard 200 amp three phase QO panel also the other thing I will bring up to your attetion the NOQD tub is much larger than standard QO tubs { 20 inch vs 14.5 inchs }

So check with your POCO to see if they can changeover from Delta to Wye system then you can able use all phase legs without issue { the key issue is the numbers of transfomer cans on the POCO post } but once you switch over to Wye the voltage on line to line will be change to 208 instead of 240 volts.
Most equiment which they are wired on 240 volts will work on 208 volts but not all will work very well so double check the nameplate info.
{ electric water heater and electric stove will work on 208 but it will take little longer to get the heat going due it will reduce the heater wattage by 25% }

I know you will ask us more question later.

Oh yeah for the uility closet make sure you keep a space open front of the load center.

Merci,Marc
 
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Old 05-31-10, 02:37 PM
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Thanks for the info Marc. I'll look at the QO line of panels; sounds like they might fit our needs a little better.

Edward

Originally Posted by french277V View Post
Speaking of 3 phase delta system I know they used the delta system when they were used for central A/C unit and some case they used delta system to run the garage or workshop where you have a bit of three phase motours.

I want to give you a head up be extra carefull with delta leg aka Wild leg or other words that will result if you used the wild leg to netural the voltage will be 208 volts so if anything on 120 volts it will make a magic smoke real quick.

The other thing is with delta system the delta leg will have smaller phase conductor than other two { this is common used in older resdentail area }

The SqD NOQD panel is bolt on { but it can have push on capitcy as well} and it will cost some how more than just standard 200 amp three phase QO panel also the other thing I will bring up to your attetion the NOQD tub is much larger than standard QO tubs { 20 inch vs 14.5 inchs }

So check with your POCO to see if they can changeover from Delta to Wye system then you can able use all phase legs without issue { the key issue is the numbers of transfomer cans on the POCO post } but once you switch over to Wye the voltage on line to line will be change to 208 instead of 240 volts.
Most equiment which they are wired on 240 volts will work on 208 volts but not all will work very well so double check the nameplate info.
{ electric water heater and electric stove will work on 208 but it will take little longer to get the heat going due it will reduce the heater wattage by 25% }

I know you will ask us more question later.

Oh yeah for the uility closet make sure you keep a space open front of the load center.

Merci,Marc
 
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Old 05-31-10, 09:52 PM
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Ed.,

Here the photo what the three phase main lug look like and most case you will have to order the cover seperate.

Volia here the photo.



The price will varies a bit but the three phase load centre useally found in electrical supply centre but the big box store may make a special order for you. { not always the case }

Merci,Marc
 
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