LV Switchgear Upgrade

[caoimhin]

Hi there,

I am currently working on in plant in the UK in which the Main Distriution Boards and Sub Distribution Boards are over 30 years old. I feel that all the above gear is due for replacement.
I know that the SDB's have no earth leakage protection for socket outlets etc. However I need some more genuine reasons as to why this gear should be replaced. What I need is a comparison of todays switchgear with those of 30 years ago and the reasons as to why 30 year old switchgear would not be acceptable today.

Any help would be appreciated.

 

[reabs]

Have a look at schneider electric's circuit breakers (Merlin Gerin) esp compact NS. They should tell you about cascading (using cheaper breakers downstream) and discrimination (knowing which circuit caused the fault). Another manufacturer is CBI.

 

[dpc]

One important criteria (to me, anyway) is the availability of replacement parts from the original manufacturer.

If these are circuit breaker panels, testing of the old breakers is necessary to determine if they are still functional.

 

[Ahr35181]

caoimhin,

I would begin by looking at the periodic I & T reports / test results, & look for any increasing number of faults due to age & deterioration, & any comments made about deviations from current standards.....If you have any reports?? If not I would have one carried out ASAP. What’s the rest of the installation/s like?

RCD's can very easily be retrofitted external to the DB's.

We have switchgear in excess of 30 years old still going strong today.

With respect to DB's, those built to more recent standards have better insulation & even have earth bars!!! Several years ago we replaced a fair few fuse boards which had flimsy pieces of asbestos in from of each bus bar & non insulated fuse bases.

Alan

 

[caoimhin]

Thanks Ahr35181,

I'm worried about carrying out unneccessary tests as the plant has been idle for over 10 years. During that time it would be safe to assume that all the boards would have been subject to ingress of moisture etc. There is also no segregation between different sections of the boards. I know you have said that you still have switchgear that is over 30 years old but are you on the limit of it's lifespan?

 

[Ahr35181]

"I'm worried about carrying out unnecessary tests as the plant has been idle for over 10 years."

I would personally have a FULL I & T carried out on the whole site. Depending on the size of the site, sample invasive I & T, the results of which will help you decide if the rest of the installation/s require full invasive I & T or just a visual Inspection.

"I know you have said that you still have switchgear that is over 30 years old but are you on the limit of it's lifespan?"

Like I said...."still going strong today", although large sections of our older sections of plant have recently been made redundant Aalong with a lot of staff!!) for production reasons.

Alan

 

[jbartos]

Suggestion: The major criterion should be nature of changing loads. If there are more nonlinear loads coming, the old switchboard will be affected by the higher harmonic content, spikes, etc. Also, the load growth should not be overlooked. However, if the loads tend to stay as per the original design basis, the existing switchboard can last another decade(s). Usually, the management is aware of life-cycles of major electrical hardware. It is relatively easy to obtain and compare. Exercise a high level of diplomacy with your superiors.