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Kevin
Kevin, Licensed Electrician
Category: Electrical
Satisfied Customers: 2931
Experience:  29 years as a Licensed Electrical Contractor in Illinois, 5 year college Electrical Instructor, Former Electrical Inspector, Diploma in Digital Electronics, Former Illinois Licensed Home Inspector
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I have a 200 am disconnect between my meter base and 150 amp

Customer Question

I have a 200 am disconnect between my meter base and 150 amp service panel. I have 4/0,4/0,2/0 aluminum service wire going to meter base and from meter base to disconnect. My problem is the 4/0,4/0,2/0 is too big for the service panel lugs. Question is can I run a smaller wire from disconnect to service panel?
Submitted: 1 year ago.
Category: Electrical
Expert:  Kevin replied 1 year ago.
Hello.....my name is ***** ***** I will be happy to assist you with your electrical question. My goal is to exceed your expectations on Just Answer!
1) How many amps is the service into the home? 150 or 200 amps?
2) What is the approximate distance from the disco switch to the panel?
Customer: replied 1 year ago.
200 amp service into the home and the disco switch is approx 3' from the panel
Expert:  Kevin replied 1 year ago.
Thanks for the replies.
1) Why is the main panel only rated at 150 amps, yet the incoming service is 200 amps? Is this a new install or an existing installation?
2) Does the panel contain a 150 amp main breaker?
Customer: replied 1 year ago.
It's a new install in an old two room building that was relocated and is being turned into an office. The service will be new the panel is not. Only running a couple of lights and an a few receptacles. Only appliance is a computer and a small 110 a/c window unit. The panel doesn't have a 150 amp main breaker.
Expert:  Kevin replied 1 year ago.
Is the 200 amp disco switch a fusible switch or does it contain a 200 amp main breaker?
Customer: replied 1 year ago.
200 amp main breaker
Expert:  Kevin replied 1 year ago.
Thank you for the confirmation.
1) The inside main lug sub-panel also needs to be rated as a 200 amp panel. Reason being is that the 200 amp main breaker disco switch would allow "over fusing" on a 150 amp rated panel. Even though the sub-panel is protected upstream with the use of the disco breaker, it is considered as being "over fused". Obviously, you cannot install a smaller amp rated disco main breaker since the incoming service is 200 amps.
2) Depending upon the total distance from the exterior meter to the panelboard, most local electrical inspectors will allow a maximum of 5 to 6 feet where the service entrance conductors penetrate into the home and a separate disco switch is typically not required and a main breaker panel can be installed. The 200 amp main breaker would act as the means of disconnect to the service.
3) Even if the 150 amp sub-panel would be considered as a tap off of the 200 amp feeder, it would require a 150 amp overcurrent protection and you don't have that since the panelboard is a main lug sub-panel.
Hope this helps………If you have any additional questions, let me know and I’ll be glad to answer them for you.
Otherwise, don’t forget to rate me before you log Off.
The next time you have an electrical question, you can also request for me at: http://www.justanswer.com/home-improvement/expert-your-electrician ……….Thanks…………..Kevin!
Expert:  Kevin replied 1 year ago.
If you have any additional questions, let me know and I’ll be glad to answer them for you. Otherwise,don’t forget to rate me before you log Off.