Gummed up disconnect

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masterinbama

Senior Member
Have a 400 amp 250volt disconnect that the lube on the blades has gummed up and is keeping them from closing. I was able to clean and relube the mechanical parts and have them working like new. Need something to put on the actual blades and clips.
 

masterinbama

Senior Member
There is a grease that Square D put on from the factory, but 30 years on the West side of a building has cooked it down to a gummy substance. These are service disconnects that rarely get used. Got the mechanism working fine with CRC White grease, can't use it on the blades though.


BTW, yes it is deenergized.
 

meternerd

Senior Member
Location
Athol, ID
Occupation
retired water & electric utility electrician, meter/relay tech
If it's not a load break disconnect (you don't lube those because of the arcing), you might try a LIGHT coating of contact grease such as No-OX or Oxiban. Don't use Alumalox or Noalox (for aluminum wire) though, because it hardens over time. We use it on meter stabs when they're hard to push into the socket. Lasts for many years. POCO will probably give you some if you ask 'em.
 

PetrosA

Senior Member
You're probably done by now, but as long as the old grease hasn't turned into a varnish from heat, all you need to do is mechanically remove it and clean the blades and wipers with the mineral oil. If it's started to convert into a varnish (hard layer) you might need to scrape it lightly with a plastic scraper or use some kind of penetrating oil to dissolve it, then clean with mineral oil and use a mineral oil based grease to coat it.

The NO-OX meternerd mentioned, and probably the other grease as well (can't find any info on that one at all...) are probably both mineral oil based greases. You might find Ilsco DE-OX locally as well. I use the Ilsco product for any AL connections since it's clear and doesn't stain my clothes. It's also a mineral oil based grease and as such is safe to use on any electrical connections. For the oil, you can just buy the cheap stuff they sell at drug stores as a laxative. It's pretty much the same stuff used in oil cooled transformers and switches and some electric heaters.
 

kwired

Electron manager
Location
NE Nebraska
I have a tube of grease I got from supply house - years ago for use on disconnect switches. It may be hard to read information on the tube by now but it was some kind of dielectric grease designed for that use. Any time I run into a disconnect that is sluggish I put a little on the knife surfaces and operate the disconnect a few times to work it into where it is needed (best to disconnect the supply voltage) and it makes a world of difference in performance. I want to say it was a 3M product, I'll maybe post later if I can read enough info on the tube to know what it is. I bet I've had this tube for more then 10 years and it is still over 75% full (toothpaste style tube).
 

Jraef

Moderator, OTD
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
For a hinged joint and/or fuse blade clamps, avoid anything with graphite, Teflon or metal particles such as titanium, which is what is in noalox, because they get worse (higher resistance) over time when exposed to air through repeated use(as opposed to a joint that gets made once and left alone). The only exception is silver, such as Cool Amp Conducto-Lube, which is specially designed for this propose. If you don't want to go for that expense, numerous people recommend a high temperature thermal grease like Dow Corning Molykote BG20, which despite the name does not have molybdenum in it.
 

Jraef

Moderator, OTD
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
I used a Square D product for the mechanicals, (one I bought for some 5KV gear's mechanicals) and cleaned the gummy grease off the blades to get it working.
Most of the equipment vendors who sell or include a packet of grease for their gear are re-selling you Molykote. When I worked at Siemens, what's what we did. Dow Corning makes it really easy by allowing it to be bought in small tubes with blank labels so that the equipment vendor can put their own part number on it and resell it for some exorbitant price.
 

kwired

Electron manager
Location
NE Nebraska
I have a tube of grease I got from supply house - years ago for use on disconnect switches. It may be hard to read information on the tube by now but it was some kind of dielectric grease designed for that use. Any time I run into a disconnect that is sluggish I put a little on the knife surfaces and operate the disconnect a few times to work it into where it is needed (best to disconnect the supply voltage) and it makes a world of difference in performance. I want to say it was a 3M product, I'll maybe post later if I can read enough info on the tube to know what it is. I bet I've had this tube for more then 10 years and it is still over 75% full (toothpaste style tube).

After looking at the tube I have, it has been around a while, and has had more used then I realized - but still has a lot in it. Not the easiest to read anymore but I was able to make out Dow Corning and BG20, probably same product Jraef mentioned.
 

ATSman

ATSman
Location
San Francisco Bay Area
Occupation
Electrical Engineer/ Electrical Testing & Controls
The Trio

The Trio

We have found over the years that any grease that has a petroleum base tends to harden over time. In fact I would say that 90% of the problems we find with LV and MV equipment (circuit breakers, transfer switches, etc) are mechanical and due to dried grease. The roller bearings, linkages, gears and pivot points get all gummed up causing AFCB to "trip free" and transfer switches to not transfer or sit there and burn up. The older the equipment the worse it gets unless it has had the PROPER maintenance thru the years. And just because there is a current inspection sticker on the panel doesn't mean that it has been properly PM'd. We have rewired plenty of older ATS units that have burnt up due to improper maintenance even though the equipment had annual "maintenance" performed by another manufacturer. In this area there is still a lot of older equipment (45 to 50 yrs) out there that produces a steady stream of business for us. We tell our customers "Dried grease is our friend" ;)
The Mobil grease in the attached photo is the best we have found so far and does not tend to harden over time. This is the same grease that GE ships with some of their LV and MV switchgear and private labels. It is a red synthetic grease that is non-conductive and can be used on breaker electrical stabs, finger clusters and mechanical parts as well. The CRC spray cleaner and lubricant work great also. DO NOT USE WD-40!
 

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meternerd

Senior Member
Location
Athol, ID
Occupation
retired water & electric utility electrician, meter/relay tech
OXiBAN Pic

OXiBAN Pic

Here's the OXiBAN. Not sure how old it is, though. May not be available. Great stuff, though. The other stuff I mentioned is called NO-OX-ID. Still available.
 

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ATSman

ATSman
Location
San Francisco Bay Area
Occupation
Electrical Engineer/ Electrical Testing & Controls
Disconnect Use

Disconnect Use

Forgot to mention that a thin coat of this Mobil red grease can be used to lube the knife blades of a disconnect switch but not if it is of the flat contact design such as the type used in circuit breakers.
 
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