MCC Maintenance Spares 1

[NCTHAI]

Hi All,

Can any one share the process of deciding about maintenance spares for HV / LV Switchgear and MCC?

What should be the basis to select the spares for MCC for 1 year, 3 year, 5 year and 10 year of operation and maintenance?

Any recommendations, guidelines, papers or reference standards shall be useful.

Thanks in advance for your help.

NC

 

[ScottyUK]

If you're the O&M contractor or the maintenance engineer responsible for the equipment then the more spares you can get your hands on, the better. Generally we work on a spares complement of about 10% of the asset value.

 

[NCTHAI]

Thanks for the suggestion. We are looking for some thumb rule ... like 5% of all installed components or different period of operation... general philosophy / rule to begin with and then customise for different factors like cost, availability, installed quantity, reliability, failure rate etc....

Any thoughts on this line??

NC

 

[ScottyUK]

Like I said, I'd start with about 10% of the equipment value if you're including things like incoming ACB's and the protection relays. They're high value items, so it pushes the value of the spares holding up quite quickly.

If you're using MCCB's rather than fuses make sure you have plenty spares - once they are end-of-lifed by the manufacturer it can get very difficult to find physically interchangeable parts. I think IEC gear is worse than NEMA types in this respect because NEMA MCCB's have standard frame sizes and designs. Consider likely failure rates and ease of obtaining spares. Look at any custom components such as auxiliary connectors, plastic mouldings, plug-in modules, interlock mechanisms, etc.

 

[NCTHAI]

Thanks you the suggestion. They are of great help!!

regards,

NC

 

[Zogzog]

When it comes to things like ACB's if you are smart you can have spares that will work for many different applications. Stay clear of fixed trip settings for example, having a spare that has a modern programmable trip unit can act as a replacement for older ACB's with series or fixed trip settings simply by changing settings.

Manually operated breakers are good for spares as well over electrically operated ones unless you really need them to be EO (Like part of a transfer scheme)

We actually stock ready to go spares for some of our customers, instead of buying them they "rent" them to be on hand fully refurbished and able to have on site within hours if needed.

 

[NCTHAI]

Zogzog,

Thanks for your suggestions!

"We actually stock ready to go spares for some of our customers, instead of buying them they "rent" them to be on hand fully refurbished and able to have on site within hours if needed." This is new concept for me. I have seen this type of agreements / arrangements of capital spares of high value items - like spares for small /medium size turbines and larger pumps but not for MCCs.

NC