rhamblin
Senior Member
- Location
- Kaukauna, Wisconsin
I work in a printing plant. About a year ago, one of our presses had some wiring "upgraded". This was not overseen by an engineer.:happysad: Recently I was called out to find out why the plates weren't kicking in. This is done by energizing a 24V DC valve. There are 6 valves per module, and 9 modules on this press. I discovered the fuse holder was in bad shape and that it had a 20 amp fuse in it. But the wire running to and from the fuse holder was 16 AWG. So it should probably have a 10 amp fuse in it.
Well after burning through a 10 amp & 12 amp fuse I replaced it with a 15 Amp. Later, I put an amp clamp on it to find out that we are drawing 13.99 amps when the plates are kicked in (valves energized). My first thought was that I would have to re-pull larger wire throughout the 130' long press. And then through each of the 9 modules. :jawdrop: Not looking forward to that.
Looking for a simpler work around, I checked out 240.21, to see about increasing the horizontal line, that runs down the press. And tapping off of it and not increasing the size of the wire going through the modules. If I were to do this the distance from the tap to the final valve would be between 10-25'. So then I looked at 240.21(B)(2), however the final connection between the valve and the last junction box is run with SO cord. So this would seem to eliminate that option.
Then I thought, since this whole circuit is fed from a DC Power-supply, maybe it could be considered a Class 1, 2, or 3 circuit. So I grab my 2011 NEC code book (in WI we haven't upgraded yet to 2014), but I am not sure what dictates the difference between a Class 1, 2, or 3 circuit.
Any help/suggestions for a simpler work around on the press or explanations on the Class 1, 2, 3 circuitry would be much appreciated.
Well after burning through a 10 amp & 12 amp fuse I replaced it with a 15 Amp. Later, I put an amp clamp on it to find out that we are drawing 13.99 amps when the plates are kicked in (valves energized). My first thought was that I would have to re-pull larger wire throughout the 130' long press. And then through each of the 9 modules. :jawdrop: Not looking forward to that.
Looking for a simpler work around, I checked out 240.21, to see about increasing the horizontal line, that runs down the press. And tapping off of it and not increasing the size of the wire going through the modules. If I were to do this the distance from the tap to the final valve would be between 10-25'. So then I looked at 240.21(B)(2), however the final connection between the valve and the last junction box is run with SO cord. So this would seem to eliminate that option.
Then I thought, since this whole circuit is fed from a DC Power-supply, maybe it could be considered a Class 1, 2, or 3 circuit. So I grab my 2011 NEC code book (in WI we haven't upgraded yet to 2014), but I am not sure what dictates the difference between a Class 1, 2, or 3 circuit.
Any help/suggestions for a simpler work around on the press or explanations on the Class 1, 2, 3 circuitry would be much appreciated.