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Answer for Canada, USA and countries running a 60 Hz, 120/240 volt, split supply service.
The main distribution panelboard has to have a main disconnect. This has been in the electrical regulations since the late 50's.
If the sub panel is in the same home under the same roof line, the sub panel enclosure does not need a main disconnect because it is just another branch circuit. Connecting a sub panel to a separate free standing garage or workshop is a different scenario and is governed by a different set of electrical code regulations.
What needs to be done to the panelboard is physically remove the neutral bonding screw. This is the screw that bonds the panelboard enclosure to the neutral bus. By doing this it stops a secondary ground pathway for a fault current from the sub panelboard to flow back to the main panelboard on the sub panel's neutral feeder.
The electrical code requires that there is only one position on an electrical distribution service where the distribution enclosure and the neutral bus join each other. That is at the main disconnect of the first over current device, which is the main service disconnect breaker or a fused disconnect switch whichever your system uses..
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What is a sub panel?
A sub-panel is always fed from a main panel. The main panel is situated where the electrical service wiring first enters the main structure on a dwelling plot or building site.A sub-panel can be situated within the same building as the main panel or it can be in a subsidiary building or structure (such as a garage, garden shed or workshop) that is separate from the main building.More informationA sub-panel is another name for a secondary breaker box, just as "the main panel" is another name for "the main breaker-box"."Breaker-box" and/or "panel" are just alternative short names that are used instead of the full name "circuit breaker box".
How do you connect 200amp from main panel to sub panel to the lug of the min panel to lug of sub panel?
Not exactly sure what your question is and you need to make sure you are in compliance with electrical code for your jurisdiction. But, generally speaking you install a large breaker (let's say 100A 2 pole breaker to power the sub panel) just as you would install any other breaker in the presently used (hot) panel, and the proper sized cable then goes from old to new and terminates on the main lugs of the new panel. Ground and neutral are usually isolated from each other in the sub panel but depends on other factors as to location of the sub panel, etc.
Can you put a 60amp breaker and a 50amp breaker on a 60amp subpanel just as long as they are not being used at the same time?
You can. Using these size breakers in a 60 amp sub panel might be pushing the limit for breaking the sub panels feeder breaker. The breaker feeding the sub panel will have to be no bigger than 60 amps because of the main bus bar capacity of the sub panel. It would be better to install a 100 amp sub panel and then there would be a bit of a buffer and you will have the ability to add additional small load circuits.
What size breaker do you use for a 100 amp sub panel?
A 100-A sub-panel would be fed from a 100-A breaker.
What should you do if your 200A breaker panel is full and you need to add three forty amp two pole singal throw breakers?
First you need to determine if addition of the new breakers will exceed the 200A service under normal operating conditions. If so you will need to go to power company and increase service and put in a larger main panel. If you have the capacity for the extra current you can add a sub-panel and add the breakers there as well as the breakers you will remove from main panel to accommodate the sub-panel breaker. Another way depends on what breakers are in current panel. There are some breakers that can be duplexed in the same space as a single breaker.
I have a Transformer 480 primary 208 secondary feeding 1 200amp mb 42 space panel I need to feed a subpanel 6 ft away I'm thinkin feed through lug at top of bus or at feed through MB suggestions?
The sub-panel need to be fed from the main panel, by way of a circuit breaker connected to one of the breaker locations. Or if your sub-panel has a main breaker installed you can feed from the main panel with a sub-feed lug kit. This looks like a breaker, but is only a point where you can branch off the sub panel.
What is a sub panel?
A sub-panel is always fed from a main panel. The main panel is situated where the electrical service wiring first enters the main structure on a dwelling plot or building site.A sub-panel can be situated within the same building as the main panel or it can be in a subsidiary building or structure (such as a garage, garden shed or workshop) that is separate from the main building.More informationA sub-panel is another name for a secondary breaker box, just as "the main panel" is another name for "the main breaker-box"."Breaker-box" and/or "panel" are just alternative short names that are used instead of the full name "circuit breaker box".
How do you connect 200amp from main panel to sub panel to the lug of the min panel to lug of sub panel?
Not exactly sure what your question is and you need to make sure you are in compliance with electrical code for your jurisdiction. But, generally speaking you install a large breaker (let's say 100A 2 pole breaker to power the sub panel) just as you would install any other breaker in the presently used (hot) panel, and the proper sized cable then goes from old to new and terminates on the main lugs of the new panel. Ground and neutral are usually isolated from each other in the sub panel but depends on other factors as to location of the sub panel, etc.
What would happen if a 200 amp breaker is used in a 100 amp sub panel?
There are two things to think about here. First of all a 200 amp breaker will not physically fit into a 100 amp panel. This is so designed because the panel buss is not designed to conduct 200 amps before the current is cut off. A 100 amp rating on the panel is the maximum amount of current that the manufacturer states, that can be handled safely. Second if the 200 amp breaker is in the main panel then everything downstream from that breaker has to be rated for 200 amp conductivity. The wire size will have to be 3/0 from the breaker to the first over current device in the sub panel which will be the sub panel's main breaker. The sub panel can not be a load center but will have to be a combination panel. I doubt that the 100 amp sub panel's main breaker lugs would be large enough to connect the 3/0 cable.
How do you wire a garage sub panel box from a 100 amp breaker in the house main panel?
you propaly can't sub panel from 100 amp panel. Just not enough amperage to be worth while. i had to up grade t a 200 amp main first and then I was able to take a 60 sub panel from that.
Can you put a 60amp breaker and a 50amp breaker on a 60amp subpanel just as long as they are not being used at the same time?
You can. Using these size breakers in a 60 amp sub panel might be pushing the limit for breaking the sub panels feeder breaker. The breaker feeding the sub panel will have to be no bigger than 60 amps because of the main bus bar capacity of the sub panel. It would be better to install a 100 amp sub panel and then there would be a bit of a buffer and you will have the ability to add additional small load circuits.
What size breaker do you use for a 100 amp sub panel?
A 100-A sub-panel would be fed from a 100-A breaker.
What should you do if your 200A breaker panel is full and you need to add three forty amp two pole singal throw breakers?
First you need to determine if addition of the new breakers will exceed the 200A service under normal operating conditions. If so you will need to go to power company and increase service and put in a larger main panel. If you have the capacity for the extra current you can add a sub-panel and add the breakers there as well as the breakers you will remove from main panel to accommodate the sub-panel breaker. Another way depends on what breakers are in current panel. There are some breakers that can be duplexed in the same space as a single breaker.
Do you need a main disconnect on the feeder wires running to a detached garage running from the box in the house?
Yes you do. The detached garage will either be fed with a single circuit or a sub panel. The wire feeding the garage will need to be protected and that is the purpose of the breaker (disconnect). The breaker size will be determined by the size of the wire that is used on this circuit.
Can you add a second main breaker box to control breakers in the out buildings on a farm?
Yes, you can add a subpanel or second main breaker box to control breakers in outbuildings on a farm. This subpanel will be supplied power from the main panel in your primary building using appropriate wiring methods and breaker sizes. Make sure to consult with a licensed electrician to ensure proper installation and compliance with local electrical codes.
Is the main circuit breaker is a sum of the sub circuit breaker?
Typically yes because that is what makes sense. However, the subpanel could have the same size breaker as long as the panel were rated for that amperage and the wire sizes were appropriate.
What size breaker do I need on the main panel to run a 2-60 amp breakers and 2-40 amp breakers on a sub panel?
You need to calculate how much the total current is likely to be at any moment. It's probable that the total load will be less than the sum of the individual breakers, 200 amps, but how much less depends on local conditions.
