shutting down switchgear for winter
shutting down switchgear for winter
(OP)
We had a pump station rebuilt last fall. The Plant manager decided to shut power to the building off during the winter.
Two circuit breakers in the mcc had problems upon start up last week. One of the breakers started working after the handle was operated many times. The other breaker was replaced.i opened up the bad breaker to find lots of corrosion inside as well as evidence of a nice arc flash.
We are located in New Hampshire so the temp in that building got down to around zero.
This pump station is critical during the dry summer months.My concern is the other breakers in the mcc being corroded also.
My report to the plant manager is going to state that we need to keep this building heated during the winter months and i am suggesting that a tech from the mcc manufacturer come look at the remaining breakers. This is 1600a 480v switchgear and i am concerned that this gear will not be reliable when needed and that the danger of arc flash is increased because of internal corrosion of the breakers.
any thoughts?
this breaker was NEW 6 months ago. the picture is bad but you can see the arc burn and the corrosion
Two circuit breakers in the mcc had problems upon start up last week. One of the breakers started working after the handle was operated many times. The other breaker was replaced.i opened up the bad breaker to find lots of corrosion inside as well as evidence of a nice arc flash.
We are located in New Hampshire so the temp in that building got down to around zero.
This pump station is critical during the dry summer months.My concern is the other breakers in the mcc being corroded also.
My report to the plant manager is going to state that we need to keep this building heated during the winter months and i am suggesting that a tech from the mcc manufacturer come look at the remaining breakers. This is 1600a 480v switchgear and i am concerned that this gear will not be reliable when needed and that the danger of arc flash is increased because of internal corrosion of the breakers.
any thoughts?
this breaker was NEW 6 months ago. the picture is bad but you can see the arc burn and the corrosion






RE: shutting down switchgear for winter
I suggest you get an NETA testing company in there to give you a independent 3rd party view of the situation. The OEM is just going to see this as a sales oppurtunity. www.netaworld.org has a list of certified companies in your area. They will be able to do all the testing and provide recommendations.
Breakers that have corrosion or fail testing can be remanufactured at a fraction of the cost of replacement, depending on thier size (Small ones are better to just replace), that is my speciality.
RE: shutting down switchgear for winter
It is not clear from you post if the 'arc' occurred when you operated the breaker or was already there. So not sure there is something else in play.
What is being pumped? What type of environment? Expanding the review of elements beyond electrical may be necessary.
Rafiq Bulsara
http://www.srengineersct.com
RE: shutting down switchgear for winter
Im guessing the arc occurred when the main breaker was closed this spring.The load bang of the 1600 amp main breaker closing probably caused the operator to not hear the bad breaker arc.
RE: shutting down switchgear for winter
Are breakers rated for outside applications possible for your installation? That might fix the problem as well.
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If it is broken, fix it. If it isn't broken, I'll soon fix that.
RE: shutting down switchgear for winter
RE: shutting down switchgear for winter
RE: shutting down switchgear for winter
Your thinking may be valid, but asking mfrs is not going to help in this situation. You need to hire a testing company to go through (check and test) all affected equipment and breakers. Perhaps a second opinion of a professional engineer, if this site is so important.
Policy of turning off power may also need to be reviewed. It is electrically helpful to keep the lines, switchboard and transformers energized, so if there is a developing fault, you catch it sooner than later and it is keeps some heat up too. I hope this policy of turning power off is not related to saving energy somehow.
Rafiq Bulsara
http://www.srengineersct.com
RE: shutting down switchgear for winter
FAQ237-1157: Information on what to do after water damage
As to testing, a NETA testing agency is a great idea, but I would also investigate whether or not the MCC mfr has their own service group that can re-certify that gear with regards to warranty. I know the majors such as Siemens, Eaton, and Square D do have their own service groups, not sure about A-B (because they don't sell switchgear, which is where the money is). Most of these groups are NETA certified as well. If they won't re-warranty it, then I would go with an independent NETA company for the reason Zogzog gave.
Strip heater in the bottoms of each MCC section is the way it is usually done, no need to build extra walls and heaters etc. All you have to do is keep the temperature above the dew point. Just make sure whatever is feeding power to the strip heaters is getting power too!
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RE: shutting down switchgear for winter
RE: shutting down switchgear for winter
-Brad
RE: shutting down switchgear for winter
Rafiq Bulsara
http://www.srengineersct.com
RE: shutting down switchgear for winter
I agree a few strip heaters could help prevent the issue. In the pipeline industry, we had dozens of Art500 EP boxes & found a small heater and a bottom EP vent was sufficient to keep the boxes dry.
Could you also tape heavy plastic over the panel face to reduce air leakage; then remove in the spring?
RE: shutting down switchgear for winter
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If it is broken, fix it. If it isn't broken, I'll soon fix that.
RE: shutting down switchgear for winter
I'm having the gear inspected and cleaned. we are going to wall off the area that houses the mcc, softstarts and plc and keep it heated for next year
RE: shutting down switchgear for winter
Another note, being NETA certified company and following NETA standards are not the same thing.
Now to be clear about both of the above statements, I am not saying a non NETA testing company (OEM attached or not) cannot do the job right, but take a look at the requirements of a NETA testing company and you can see some advantages to using one (I am currently not a NETA company for the record, but was a level IV)
RE: shutting down switchgear for winter
In the past I've provided support for several clients who had to deal with moth-balled gear in various voltage ranges.
Some of the equipment was kept "live" with very reduced load, such as a medium voltage lineup kept hot through at 10 MVA transformer to provide power to a 300 kVA transformer feeding some environmentally sensitive equipment.
Others were, as you said, completely dead, but future use was expected.
It was fun explaining to management that even though you didn't USE the capability for years, it still needed considerable care and maintenance to keep it from becoming expensive junk.
As for service groups, I've worked for and with both NETA and non-NETA and OEM groups, and your level of service can be equally good (or poor) with both. I too held NETA level IV certification. I know a bit about the electrical testing and maintenance business.
You need to develop a good relationship with a company that will provide you with the services you need. This is not an easy task, because there are some real "snake-oil" salesmen out there who will take you to the cleaners, and there are a lot of people in the field who "go through the motions" in their work without understanding why they do what they do. It's a tough business to manage, and it makes our job as users more difficult.
old field guy
RE: shutting down switchgear for winter
Maybe you also need some drip protection on this panel.