ARC FLASH FROM "TIN WHISKERS"

[TVH]

Interesting Arc Flash info on a phenomenon known as "Tin Whiskers" on bus bars:

Arc flash incident in 690V switchboard due to tin whiskers

An arc flash occurred during de-isolation switching in a 690V switchboard, causing a significant current surge but fortunately no injuries. The incident was attributed to 'tin whiskers,' which are conductive strands that grow from bus bars, reducing the air gap and creating a pathway for the arc.

toolbox.energyinst.org

 

[TVH]

Good info.

 

[ModbusMan]

Hoo-boy... I've heard of zinc whiskers causing problems with circuit boards when lead was removed from solder, but this is the first I've heard of them growing on bus bars. Something for me to shoot over to our reliability guy!!

 

[garbo]

Side note while working at a large candy plant years ago the room they made air puffed candy ( air bons ) from sugar went thru 120' long vacuum tunnels were they grew to over 5 /8". Machines were old and produced sugar dust during production. Starters were in conventional enclosures instead of dust tight. So much sugar would build up on starters the 480 volt would flash over luckily only taking out one or two fuses. Thus occurred at least once a year. Was on our list to install all of the starters in a large Hoffman panel but they scrapped it.