LT Switchgear Upgrades

Quote "now i want upgrade the 5.5kw module to 22kw module."

I am not sure what you mean by module. Are you referring to your panel?

I think 'module' here is MCC cubicle for the motor starter.

In this case, space (dimension) definitely will be a problem. In addition, the starter terminal connection (plug-in bushing) will be under-rated. I would suggest you to contact the MCC vendor. The vendor may have compact starter to fit in smaller space and the plug-in bushing can be replaceable with higher rating.

- MS

It is possible.However you have to do little bit of study.

Is it draw out module or fixed module ?

If it is fixed module ,you have find out the size of the module and ascertain whether the bigger size components can be accomodated.

List out the components and wires required for 22 kw starter.

Remove the existing components of 5.5 kw starter.

Fix the new components for 22 kW starter and rewire the circuit.

If it is drawout module check the fixed contacts of the module which gets contact with the busbar for adequacy of rating.

in my opinion for 5.5 and 22 kw ratings the contacts will be same rated to 100 Amps if so no problem.

Please ensure 22 kw is also DOL starting.

If it is going to be Stardelta starting the module size may not be adequate to accomodate all the components since for SD starter the number of components are much more than the DOL starter.

Before making any changes, you will need to verify the capacity of each affected part of the MCC. Most MCC's have one horizontal main bus, and several vertical branch buses (one for each module stack). The main bus is designed for the full load capacity of the entire MCC. The branch bus is usually lower capacity.

Sum the currents of all the existing loads on the branch bus where the new load is to be attached, then add the current of the new load. Compare that total to the capacity of the branch bus. Repeat the same exercise with all loads on the MCC compared to the capacity of the main bus. I suspect that the branch bus, and possibly the main bus, will be overloaded.

If you can't use the existing 5.5 KW cubicle, but the main bus has available capacity for the 22KW motor, there are a couple other options available.

1) You may be able to expand the MCC by adding another vertical stack at the end. If the MCC is not designed for expansion, this is usually not practical.

2. You can attach a separately-mounted starter on the side (end) of the MCC and run cable from the main bus to the line side of the new starter. I've done this a couple times where the cost of upgrading the MCC was more than the project was worth.