Both machines, the 1970’s vintage Zimmermann pattern maker’s milling machine and the Wadkin Dimension saw, are currently at sea, and they are scheduled to arrive in Boston by the end of the month. In the interim, I’ve continued to chip away at various tasks to get my shop ready.
I’ve installed most of the electrical service for the two machines. I am not a certified electrician, just someone who has done some wiring over the years, however I had a licensed electrician come by and take a look at my work and he gave me the the thumbs up.
All the EMT is installed now, coming about 90′ from the load center, though a couple of pull boxes, to the location on the wall where I have decided to place the transformer:
The transformer was hoisted up high and bolted to a couple of 2×4’s, which were in turn bolted to the brickwork behind. The incoming power routes down on the left, and travels first to a ‘Square D’ DU322 Safety Switch:
From the switch, the line travels up to a junction box, where the transition can be made to some 3/4″ flexible tubing (a requirement as the transformer vibrates slightly) and connection can then be made to the transformer. I used ‘Liquid-Tuff’ tubing, and I think it looks a lot cleaner than the metal coil BX cable housing. Easier to cut clean on the ends too.
The switch does not have a provision for the neutral wire, however this is unimportant as the neutral can be run directly through and up to the transformer and is not directly switch controlled. I verified this with the electrician of course.
The transformer is simple to wire, and clearly labeled, almost plug and play. At present I am waiting on the AWG #8 wire which will run from the load center to the transformer (ordered online), however in the meantime I have been able to install the wire from the transformer’s output side on down, as it is 10 gauge, and I could pick the small amount up I needed at a local store. The left side will have the 208v/60 input, while the right side outputs at 456v/60hz. As the output side is somewhat close to the 480v. standard, the 480Y/277 US wiring code convention is followed, which makes the wire colors for the high voltage side Brown-Orange-Yellow, with a grey neutral:
The neutral voltage is the line voltage of 456v, divided by √3, or about 1.73205…, which equals about 263v. Similarly, the neutral voltage for 208v is divided by √3 to give a value of 120v. A lot of people get confused by the fact that the phase voltages in the 208Y/120 system are separately 120v., but the line voltage measured across 2 phases is 208v. – a lot of people think it ought to be 240 volts. It’s a vector result (each phase being 120˚ apart), not a simple addition however.
The colors for the 208Y/120 input side are Black-Red-Blue, with the neutral in white. Ground wire is green. The term ‘high voltage’ is slightly misleading however, as in the big picture, systems carrying 600v or less are classified as ‘low voltage’ by the utility. Medium voltage are those applications from 601v to 34,500v, and high voltage is 34,500v and up.
The output from the transformer travels down through some more 3/4″ flexible tubing to a second junction box where it is attached to a pair of EMT-cased feeds, each going to a separate outlet with receptacle:
When 480v is employed, all the transitions out of the EMT into the junction boxes have to have plastic bushings installed.
The grey neutral wires, as they will not be used by either machine, are simply capped off in the junction boxes. I am putting the neutral in all the way to the end for what might be called ‘future considerations’. The handy thing about the 208Y/120v system is that any one of the conductors can be paired with the neutral to provide 120v single phase connection if required.
The machines will be tied to the receptacles with ‘twist-lock’ plugs as they call them at the electrical supply places (though in fact, these particular ones do not twist to lock but simply insert), and some AWG 10-gauge, 4-wire machine service cable:
I probably could have scaled down to 12 gauge for the cable, however the 10 gauge isn’t hurting anything either, except my wallet perhaps. The two metal pieces above in the picture are strain-relief connectors, and these two l’il gippers cost more than the 30′ of heavy service cable I purchased anyhow. Most of the wiring parts are not too expensive, and the global cost for copper is down right now so wire is not as expensive as it was last year.
Here I’m wiring up one of the receptacles – starting by trimming the wires to length:
Love the Knipex lineman pliers.
Then on to stripping the housing off the ends. I have come to find these sort of mechanical strippers to be the most comfortable to use:
I could work with these for hours and not get tired and they always give clean cuts:
The receptacle, a Leviton 2730 rated for 3-phase 4-wire 480v service, is attached to the cover plate, and then I connect the ground wire as a next step:
**Of course, always make sure power is disconnected before doing any electrical work. I’m sure I didn’t have to state that, but, you never know…. I’m comfortable working with this stuff, but if you’re not, by all means have a professional do the work.
The phases are identified on the receptacle as X-Y-Z, and here I’m connecting the brown wire to ‘X’:
If you look closely under the fastening tab you will see that there is an ‘X’ cast right into the black plastic.
The plug looks like this:
The terminal with the bent-over tab portion is the ground. When you install a receptacle – and this goes for 115v single phase receptacles as well – the ground terminal should be uppermost. Check back up a couple of pics and you will note that the mounted receptacle has the ‘L’ shaped terminal at the top.
Oriented this way, if the plug is partially removed from the outlet by accident, and is still electrically live, and a metal object like a bare wire or ruler, etc, happened to fall onto the connection, it will touch the ground prong and not short anything out and start a fire.
The plug separates into two halves:
At the terminal connection end the connections are clearly labeled, just like the receptacle, with ‘G’ for ground and then X-Y-Z:
I’ll leave off wiring those up for the time being.
At the other end of my shop, further developments have ensued with the wood rack, now with a clamp rack on the front:
While it might look like I have now trapped boards within the wood rack, this clamp rack is in fact hinged on one side and can be readily swung out of the way. Also, I have mounted the rack higher than previously, which allows my longest clamps to now be hung up instead of leaned against the wall.
I have realized that I only occasionally need to access the wood rack, so it is no great inconvenience to have the clamps in front like that. Besides, only the middle bay of the wood rack is actually affected, the wood in the side bays can be accessed from their side openings easily.
One more pic for good luck:
I may add another hinged panel above the clamps to store more stuff. Anything to get stuff off the floor and into a place where they can be clearly identified and found when needed. So tired of searching for stuff and scratching my head about where to place things. Slowly getting to a place on my train ride called ‘Organized’. Perhaps the next station will be ‘Productivity’ ? :^)
All for now, I hope you enjoyed the update.