How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Mike Your Own Question
Mike
Mike, Master Electrician
Category: Electrical
Satisfied Customers: 1425
Experience:  Licensed Master Electrician - OnQ Certified Data Voice Audio Video Installer
11762411
Type Your Electrical Question Here...
Mike is online now
A new question is answered every 9 seconds

I have an office in a commercial building with a 400

Customer Question

I have an office in a commercial building with a 400 amp pannal a big closet pannal I Installed new A/C and now we are pulling around 330 -370amps and my main keeps blowing
1) what is the maximum allowed
2) would a capacitor work
3) or what do you think would work other then upgrading the main. Not an option
Submitted: 3 years ago.
Category: Electrical
Expert:  Steve G. replied 3 years ago.
Hello there and welcome to Just Answer. My name is Steve and I will be assisting you today. I am an engineer with over 30 years of electrical and electronic training, repair and installation experience. I will try and answer your question accurately and precisely so that we can get you on your way.

I need some additional information from you in order to fully understand the situation.

1. What is the largest breaker in that 400A panel?
2. Can you determine what event causes the breaker to trip - AC coming on maybe?
3. What is the voltage configuration of this panel?
4. What other big loads do you have (over 50A)?

Please let me know the answers to those so that we can continue.

Regards
Steve
Customer: replied 3 years ago.
The biggest breaker would be the new four ad units that were I stalled the main is 400 amps and yes when the units run after a wile the whole main breaker popes we tested the amp pulled and it comes out to between 330 -370
Did my electrician over load the breaker of 400 I heard that 80% of 400 is the max and would a simple fix be to put a capacitor on the new ac units like a power saver 1200
Expert:  Steve G. replied 3 years ago.
I appreciate the answer but am still not clear on what is going on.

1.What size (in Amps) is the largest breaker or breakers in the panel not including the main.?
2. What is the voltage configuration of the panel? 480/277 or 120/208? Or something else?
3. What other big loads do you have (over 50A)?

Please let me know so that we can continue.

Regards
Steve

Related Electrical Questions