Busbar in MCC

Do you mean upgrading or expansion of MCC panel?...Only chanes in Busbar rating?...If it additional compartments, what about the incomer breaker rating?

It is an expansion of MCC panel. The breaker rating is 200A.

Like someone else said, good comments here require a one-line diagram.

200 amps doesn't sound like you're talking about the right breaker--the breaker of interest is the one that is protecting the busbar of the MCC, that is, either the incoming breaker on the MCC, or, for an MCC without an incoming breaker, the breaker on the feeder to the MCC.

I suspect you're telling us the rating of the breaker of the new load to be fed with the new busbar.

The 4000A busbar might be physically larger, and might need adapters to join to the existing. It's best to check. Discuss the issue with the existing MCC supplier and the additional MCC supplier.

If the existing power feed is to the 3000A-rated section and there is no additional feed to the 4000A-rated section, then there is unlikely to be any need to provide additional overcurrent protection. The converse is not true.

Hallo to PWSslack. You are correct, there might be a variation in the actual physical size of the 2 busbar's but the 3000A and 4000A ratings is only the maximum current the busbar can withstand before overheating ocure and eventual meltdown will be the result. In the question there is no mention of any additional feed. there is also no mention of whether the new busbar is going to be in series or in parallel with the existing busbar.

The amps rating of the buss bar only represents the amps that a given material can handle without adding resistance within the panel. More resistance creates heat. Ex: aluminum wire must be larger than copper alloy wire to conduct the same current value without getting hot enough to melt. Therefore it is possible to mfg. a buss bar that is an exact size replacement and increase the amps. capacity. It is also possible to provide a buss bar that is within the size requirements/tolerance specs. that will still work with the breakers, that will install as an equal but greater in amps. capacity.

Check the info/specs. for exactly what will work as a replacement in your panel. You may be b dealing with an aftermarket or upgraded component that functions well in your particular situation/panel.

TMF

As said before... The bus bar rating only indicates the maximum amps the bus bar can handle transiting through it.

Therefore, all depends on the loading you are planing to put on the Busbar.

any good advice that might come to you will need a schematic of the intended connections...

A fluid analogy to your question is: "I have a 1/2 inch pipe carrying water at 5 gal/min to my shower. Will switching to a 2.0" pipe affect the operation of my shower? The answer is, if you have room for the 2.0" pipe you will have slightly lower pressure (in your case voltage) drop across the circuit.

Question is not clear ,weather you are replacing Main bus-bars inside the MCC OR external Riser bus-bars as incomer feed connecting to MCC.bUT WHATEVER existing

bus bars rating 3000A ,new BUS BARs RATING 4000A,SIZES will not match for connection ,you better to consult your supplier.

There are two elements to this:-

1. The overall system effects of rated current, fault rating, IP ratings etc i.e. compatibility.

2. The interface between 2 different MCC sections (I assume they are different otherwise you would be buying an identical extension to your existing columns).

With regard to the extension, in all cases the parameters must equal or exceed those of the existing installation (most obvious is fault rating). If the existing MCC is rated at 80KA for 1 second, so must the extension. Pay particular attention to the earth bars.

With regard to the interface, you must be careful to respect the existing system - I am assuming you have checked that the existing busbars are already drilled/punched, you are fully aware of the jointing methods/materials, and have carefully checked the drawings or done your own measurements of the busbars. The joggle section between the two busbars can then be designed accordingly. No doubt your designer will also take into account the physical differences in enclosure size, suiting holes between the two, the arrangements for maintaining the IP rating etc.

Good luck.

Your project does not seem to me based on sound electrical engineering design practices. Why should you connect two bus bars of different ratings (a difference of 1000A) within the same switchgear (Here MCC Panel)? The entire bus system has to be uniformly rated- 3000A or 4000A rated. You can do what you have planned to do, but you must not do it. A few years down the line some other engineer who wishes to add more load on it will not even dream of having an MCC whose half the half side bus bars are one rating and the other half of other rating. I would advise you to review the project once again.

BBRaina

Dear,

Few points to take note at the sizing of the bus bar. At interconnection point surface matching would be better between bus bars. For different current rating, same width but different number of bus bars stacked together can be used. The cross section times a factor determines the max current carrying capacity of the bus bar. The clearance is the important for your impulse withstand voltage level and make sure correct size bolts and nuts are used.

Since higher current rating than 3000A should be fine but make sure the protection at the incoming remains same.