Trying to understand Combination Motor Starters

[jim dungar]

The MCC buckets' label includes the HP rating and catalog number printed on the bucket label along with the UL. So when you order a different disconneting means, a different OL, whatever, you would need to order a lable, except that you are not authorized to affix a label that has listing information on it.

No. The last labels I saw said MAX HP. I do not know of any company that puts a unique UL label in each of their MCC starter buckets.

I had several customers that regularly bought Size 2 starters to feed motor loads that other people fed with Size 1. Their rational was that they wanted the every starter (and the branch wiring) to always be capable of accepting the next larger motor than shown on the plans. Our MCCs were always shipped with UL labels.

You must have missed the specific information supplied by the OP, which said they had a 25HP starter bucket that had a circuit breaker that was sized for a 7.5HP motor. My response was to order the correct 'listed' replacement parts from the manufacturer.

 

[Jraef]

...
I had several customers that regularly bought Size 2 starters to feed motor loads that other people fed with Size 1. Their rational was that they wanted the every starter (and the branch wiring) to always be capable of accepting the next larger motor than shown on the plans. ...

This is a very very common practice in some industries, I see it a lot in the Aggregate (Rock Crushing / Asphalt) industry. Another reason they do it is to minimize down-time. They make it so that every bucket is wired exactly the same so that any Size 2 bucket can be a "universal donor" for a failed Size 1 or 2 bucket somewhere else. All they need do is change the heater elements and adjust the MCP settings. One thing that doesn't work however is that an MCP for a Size 2 will usually not adjust low enough for a Size 0 or 00 starter.

Side note: Wow, a simple discussion on the explanation of a "Combo Starter" has sure generated a lot more opinions that I ever thought it could...