Electrical Panel - Additional Load

[Eduardo Maun]

Sir,

Good morning, We have existing panel the main breaker rated 200A and sub-main/branch rated (2) 100A & (1) 63A. My Engineer suggest to add (2) 100A. I told him this will overload our main breaker but he insist that it is safe to add additional (2) 100A. How can I calculate the max. load of the main breaker can withstand. Or my Engineer is correct to add (2) 100A in the panel?

 

[Eduardo Maun]

Electrical Panel

Electrical Panel

My Engineer told me I need to know the total connected load and if the total connected exceed to 200A that's the time main breaker will overload. Well he is more experience most likely he is correct. What about the cable size in the existing panel should I need to upgrade it? and the service entrance from meter to main panel?

Thank you!

Ed.

 

[Twoskinsoneman]

Your engineer is right. Adding CBs and sub-panels is not important. What is important is doing a load calculation to determine if the service is sized correctly or requires upgrading.

 

[Eduardo Maun]

Something went wrong!!!

Something went wrong!!!

For a period of two weeks the wire from load to sub-main panel burned and we are lucky because it did not create more damage. I ask my Engineer you told me nothing will happened if we add additional load and it is safe. Now he wants me to change the wire size I'm afraid this will cause more damage and I think it will be a temporary solution but because my Engineer is got more experience than me I need to follow him even if I don't agree with him... LOL...I suggest why not call the Power Utility Provider to find out what is really the problem. If the (2) breaker for additional load cause the problem or it will create problem at the future.

Thank you.

 

[Volta]

Please describe which section of cable became damaged again. You said it it was from the load to the sub-main panel. That is difficult to understand. It seems that you should have these components:

A. Service conductors. From the utility to the main 200 amp breaker.
B. The main 200 amp panel.
C. The existing feeder conductors to the 100 amp sub-panel.
D. The existing 100 amp sub-panel.

That is all that is clear from your post. Other things you have mentioned that are hard to imagine exactly are:

E. The existing 63 amp feeder. Is this breaker in the main panel?
F. The 63 amp load, probably not relevant.
G. The new 100 amp feeder. Is this breaker in the main 200 amp panel or in the existing 100 amp sub-panel?
H. The new 100 amp load.
I. The new 80 amp feeder. Where is this breaker?
J. The new 80 amp load.

My assumptions are:
1. Your use of (2) before the amperage simply mean a "double" breaker, otherwise called "two-pole".
2. The new 100 amp breaker was placed in the existing 100 amp panel (D). Is that true? What size wire/cable was used to feed the new load (H)?

Which cable burned?

 

[Eduardo Maun]

Sir,

Sorry about the confusion from the utility provider we have MAIN DB consists of 200 amp main breaker with (2) 100 amp(existing). The existing (2) 100 amp for (2) Sub-main board. My Engineer told me previously to add (2) 100 amp breaker (new) to supply another (2) Sub-main board. One of the new Sub-main board was burned/damage. After that he told to me replace the new (2) 100 amp breaker to 80 amp & 63 amp and change the damage wire to bigger size. I told him why not consult the utility provider to find out what is really the problem he told he got more experience than me he knows what he is doing that is why I followed him even I don't agree with him LOL. But still thinking the solution he provided was temporary. Load calculation I try to figure it out.

Again thank you so much.

 

[Volta]

Sir,

Sorry about the confusion from the utility provider we have MAIN DB consists of 200 amp main breaker with (2) 100 amp(existing). The existing (2) 100 amp for (2) Sub-main board. My Engineer told me previously to add (2) 100 amp breaker (new) to supply another (2) Sub-main board. One of the new Sub-main board was burned/damage. After that he told to me replace the new (2) 100 amp breaker to 80 amp & 63 amp and change the damage wire to bigger size. I told him why not consult the utility provider to find out what is really the problem he told he got more experience than me he knows what he is doing that is why I followed him even I don't agree with him LOL. But still thinking the solution he provided was temporary. Load calculation I try to figure it out.

Again thank you so much.

If the sub-panel board was damaged, and the wire size was correct, it is likely that the connections were poor.

Otherwise, the wire was to small.

What size is the wire?

 

[Twoskinsoneman]

Sir,

Sorry about the confusion from the utility provider we have MAIN DB consists of 200 amp main breaker with (2) 100 amp(existing). The existing (2) 100 amp for (2) Sub-main board. My Engineer told me previously to add (2) 100 amp breaker (new) to supply another (2) Sub-main board. One of the new Sub-main board was burned/damage. After that he told to me replace the new (2) 100 amp breaker to 80 amp & 63 amp and change the damage wire to bigger size. I told him why not consult the utility provider to find out what is really the problem he told he got more experience than me he knows what he is doing that is why I followed him even I don't agree with him LOL. But still thinking the solution he provided was temporary. Load calculation I try to figure it out.

Again thank you so much.

Yes what size wires did you run from the new 100 cb to the 100a sub you installed?

 

[Little Bill]

Sir,

Sorry about the confusion from the utility provider we have MAIN DB consists of 200 amp main breaker with (2) 100 amp(existing). The existing (2) 100 amp for (2) Sub-main board. My Engineer told me previously to add (2) 100 amp breaker (new) to supply another (2) Sub-main board. One of the new Sub-main board was burned/damage. After that he told to me replace the new (2) 100 amp breaker to 80 amp & 63 amp and change the damage wire to bigger size. I told him why not consult the utility provider to find out what is really the problem he told he got more experience than me he knows what he is doing that is why I followed him even I don't agree with him LOL. But still thinking the solution he provided was temporary. Load calculation I try to figure it out.

Again thank you so much.

Yes what size wires did you run from the new 100 cb to the 100a sub you installed?

I think a "translator" would help here.

 

[Eduardo Maun]

The wire size 4 mm sq after the breaker/cable burned he decided to change the wire to 6 mm sq. After that the circuit for outlet was burned. Again I told him what is happening is not normal and I insist to him inform the utility provider to find out what is the real problem. I'm not sure what he will do again. I'm afraid next time it will create more damage burn the whole circuit. LOL....

 

[kwired]

The wire size 4 mm sq after the breaker/cable burned he decided to change the wire to 6 mm sq. After that the circuit for outlet was burned. Again I told him what is happening is not normal and I insist to him inform the utility provider to find out what is the real problem. I'm not sure what he will do again. I'm afraid next time it will create more damage burn the whole circuit. LOL....

The use of sq mm dimension is not common in the US - we are all familiar with AWG sizes. Looking at ch 9 table 8 12 AWG is closest size to 4 sq mm. That is only a 20 amp conductor and you are supplying it with a 100 amp breaker. That probably is a problem. The load is what determines the current but if it is a 100 amp breaker it is likely intended to be more load than the conductor is designed to carry. Even the 6 sq mm conductor he wants you to change to is pretty small for 100 amp.