Life expectancy of electrical equipment

[chiefkona1145]

Hello folks,

Has anyone ever seen a listing of life expectancy in years of things like transformer, automatic transfer switches, capacitors, wire and cable, unit substations, distribution panelboards, breakers, lighting, etc.?

I'm looking for general information and it is assuming that everything has been working fine without problems for the last 15 years. I'd hate to state in a report that 'the average equipment life expectancy is 30 years, so you have 16 years to go before you need to start replacing things'.

I am an engineer, not a contractor, and have been assigned to do a multi-building equipment evaluation and have asked a few manufacturers if they have published general information pertaining to my question and they've all come back with "never heard of such a thing". I can understand the manufacturers not sticking their necks out for fear their equipment might fail earlier than what they publish for liability reasons.

Any help would be greatly appreciated.

Thank you,

Chiefkona1145

 

[zog]

Depends, back when we took pride in manufacturing equipment life expantancies were longer than the lowest price possible crap they make now.

I work on circuit breakers and transformers every day that were built during and prior to WWII, when properly maintained this stuff will outlast anything made by any OEM today. Circuit breakers for example used to use contact mass instead of contact pressure like they do today, mechanisms were built with steel, now they use a low grade alloy. Frames were also steel, now they are plastic.

The only things better now are insulation materials and electronic trip units/monitiors/relays. Upgrade old, built to last equipment with modern insulation materials and electronics and you have something special.

 

[nollij]

I would not put specific dates on pieces of equipment as there are lots of equipment that will last longer than any of us if it is maintained and reconditioned. To know when to maintain/recondition you need to test the equipment every once in a while.

 

[Electric-Light]

Hello folks,

Has anyone ever seen a listing of life expectancy in years of things like transformer, automatic transfer switches, capacitors, wire and cable, unit substations, distribution panelboards, breakers, lighting, etc.?

Chiefkona1145

I'm not sure how "average" works, but I can speak for light bulbs. There is no solid definition and what they call "average" is not the conventional mean we're used to.

If a light bulb quotes 750 hours life average, they're quoting to 50% failure. It means that if you have 1,000 of them running at exactly the rated voltage, you can expect half them to fail at 750 hours in a large sample.

When they're on group re-lamp schedule, waiting until half the lights are out is unacceptable in most cases, so the useful lifetime to 20-25% failure maybe used and maintenance interval is shorter than lamps rated life.

Survival rate looks like a reverse S curve with a sharp drop. The slope will obviously depend on the standard deviation of useful time of components.

 

[skeshesh]

I may be wrong but I thought there was an IEEE std. that had some information regarding life expactancy. Now it may have been not in so many terms but rather when you need to TEST the equipment to see if it needs replacement, but you may be able to address the issue of life expantacy in those terms in your report. Also its possible that I read such information in specific std. for each type of equip or component (xfmr, ocpd, grounding, etc.). Or I may just be wrong and such a standard doesnt exist!

 

[masterinbama]

Depends, back when we took pride in manufacturing equipment life expantancies were longer than the lowest price possible crap they make now.

I work on circuit breakers and transformers every day that were built during and prior to WWII, when properly maintained this stuff will outlast anything made by any OEM today. Circuit breakers for example used to use contact mass instead of contact pressure like they do today, mechanisms were built with steel, now they use a low grade alloy. Frames were also steel, now they are plastic.

The only things better now are insulation materials and electronic trip units/monitiors/relays. Upgrade old, built to last equipment with modern insulation materials and electronics and you have something special.

I need some trip units for this gear Zog. Think you can help?

Seriously this gear was used until about 1981. It was installed around 1920.

 

[BJ Conner]

Hello folks,

Has anyone ever seen a listing of life expectancy in years of things like transformer, automatic transfer switches, capacitors, wire and cable, unit substations, distribution panelboards, breakers, lighting, etc.?

I'm looking for general information and it is assuming that everything has been working fine without problems for the last 15 years. I'd hate to state in a report that 'the average equipment life expectancy is 30 years, so you have 16 years to go before you need to start replacing things'.

I am an engineer, not a contractor, and have been assigned to do a multi-building equipment evaluation and have asked a few manufacturers if they have published general information pertaining to my question and they've all come back with "never heard of such a thing". I can understand the manufacturers not sticking their necks out for fear their equipment might fail
earlier than what they publish for liability reasons.

Any help would be greatly appreciated.

Thank you,

Chiefkona1145

Google Electrical equiptment MTBF and reliability. Tons of stuff out there but it may not be free. NASA and the IEEE have lots of papers on the subject.
There is even a division of engineering that deals with it. IT's a lifes work for some people.

 

[zog]

I need some trip units for this gear Zog. Think you can help?

Seriously this gear was used until about 1981. It was installed around 1920.

You still have that gear? If so lets make a deal.

 

[chiefkona1145]

Much appreciated folks

Much appreciated folks

I must admit that I knew I would get some across the board results and I thank you all for taking the time to respond.

I once worked on a project in the early 90's that still had an old knife switch, live front, switchboard in service..it was a real museum piece.

I am going to recommend to the owner of the multi-building project that he have a testing organization in place and that they perform various tests including infrared scanning of equipment and terminations.

Thanks again and have a good rest of the week.

Chiefkona1145

 

[brian john]

The only things better now are insulation materials and electronic trip units/monitiors/relays. Upgrade old, built to last equipment with modern insulation materials and electronics and you have something special.

Except these trip units may have manufacturing issues and are often obsolete in 5-10 years.