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 Post subject: BOLT LOCK PRESSURE SWTICHES
PostPosted: Tue Apr 16, 2019 2:08 pm 
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Joined: Tue Jan 19, 2010 2:35 pm
Posts: 144
Forum members. This is not an arc flash question, but you have lots of experience and I'd like you're input. We shut off a 2500 amp Square D bolt loc main disconnect switch and it took 2 (good sized) electricians to get the handle moved enough to recharge the closing spring. I'm sure this isn't normal. Has anyone had any experience like this? If so, who did you contact or what did you do to fix the problem?


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 Post subject: Re: BOLT LOCK PRESSURE SWTICHES
PostPosted: Wed Apr 17, 2019 7:14 am 
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Joined: Mon Jan 18, 2010 11:35 am
Posts: 524
Location: Wisconsin
wilhendrix wrote:
Forum members. This is not an arc flash question, but you have lots of experience and I'd like you're input. We shut off a 2500 amp Square D bolt loc main disconnect switch and it took 2 (good sized) electricians to get the handle moved enough to recharge the closing spring. I'm sure this isn't normal. Has anyone had any experience like this? If so, who did you contact or what did you do to fix the problem?


NFPA70E requires electrical equipment to be properly maintained.

Bolted pressure switches need to be exercised on a fairly regular basis, at least every 3-5 years, or else the grease hardening and dust can cause the moving parts starts to seize. The majority of the time these switches can be cleaned, and even rebuilt. There are manufacturer's service reps as well as independent firms that work on these type of switches on a monthly if not weekly basis. This is a job for experts. Simply spraying everything with a degreaser and lubricant is typically not sufficient.


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 Post subject: Re: BOLT LOCK PRESSURE SWTICHES
PostPosted: Wed Apr 17, 2019 11:29 am 
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Joined: Tue Jan 19, 2010 2:35 pm
Posts: 144
Thanks for the reply. You're right about the problems with not maintaining them. Unfortunately, if and when people purchase this kind of gear, they often don't realize that the low cost can quickly be gobbled up in maintenance and sometimes repairs. I had a 480 volt 2000 amp bolt loc switch that tripped on ground fault, but did not fully open. In the end, we had the power company de-energize the pad mount transformer so we could repair the switch. But I've never had a switch do what this one did. I mean, taking so much effort to get the switch to re-close.


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 Post subject: Re: BOLT LOCK PRESSURE SWTICHES
PostPosted: Fri Apr 19, 2019 6:02 pm 
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Joined: Sat Nov 21, 2009 10:23 pm
Posts: 110
Location: Ohio
Some Insights:

1. The SqD Bolt-lock in large sizes has always been hard to operate, I am comparing them to Boltswitch and Pringle. Their 2500 is so hard to operate it seems like there is a malfunction.

2. Let me address the Boltswitch and Pringle switches, as they close (make contact) you have zero clearance, therefore, the blade area has to be clean and lubricated, if not, that is where problems begin. Maintenance is extremely easy, if the the contact area is not pitted, all you have to do is clean with kerosene and lubricate the contact area with Vaseline. If you do this every two years the switch should not give you any future issues.

3. If you install two infrared viewing windows on the switch centerline (one each top/bottom) you can see all three phases, therefore, allowing easy and safe viewing of the contact areas with an IR camera. This is especially important since these switches are typically installed in high IE areas.

4. Many of these switches are fitted with phase failure and ground fault schemes. This presents a problem in that the switch requires a shut down of the entire switchgear to maintain those relay based systems. It is fairly simple to bring all the controls out to an externally mounted enclosure, future maintenance now becomes simple and quick.


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