Over the years I've helped install several walk-in coolers and freezers. I've noticed lately that the condensing units are coming with their defrost timers mounted in them. This often makes things more complicated for sparky when they do that. In the past they would run 2 separate circuits, one for the evaporators and one for the condensing unit with no interconnecting wiring between them. Now they need to run a larger circuit that's sized to handle everything, and they need to run a bunch of wires between the condensing unit and the freezer.
One issue that keeps coming up is how to properly wire up a disconnect switch for the freezer's evaporator. They are never drawn in the diagrams and we're left to figure them out themselves. There are a lot of wires that could have power going to them depending on what position the defrost clock is in. I am of the thought that if you turn off the switch, the entire device should be de-energized so a service person can work on it without getting shocked. The electrician often wants to just cut power to the fans and solenoid because he thinks the switch is mainly for the the convenience of the kitchen people so they can shut off the refrigeration when they need to load the box or whatever (and because that is the easiest thing to do).
When the units used to come with a loose shipped defrost clock, I would have the electrician wire it so that the disconnect behind the evaporator would cut the 2 line wires before they went to the timer. This would de-energize the entire unit making it safe to work on, but this way doesn't work when the time clock is pre-installed in the condensing unit.
The simplest freezer evaporators have N, 3, 4, and X going to them. Should I have the electrician install a 3 pole switch breaking N, 3, and 4? I think that would work. Is there another good way to do it?
One issue that keeps coming up is how to properly wire up a disconnect switch for the freezer's evaporator. They are never drawn in the diagrams and we're left to figure them out themselves. There are a lot of wires that could have power going to them depending on what position the defrost clock is in. I am of the thought that if you turn off the switch, the entire device should be de-energized so a service person can work on it without getting shocked. The electrician often wants to just cut power to the fans and solenoid because he thinks the switch is mainly for the the convenience of the kitchen people so they can shut off the refrigeration when they need to load the box or whatever (and because that is the easiest thing to do).
When the units used to come with a loose shipped defrost clock, I would have the electrician wire it so that the disconnect behind the evaporator would cut the 2 line wires before they went to the timer. This would de-energize the entire unit making it safe to work on, but this way doesn't work when the time clock is pre-installed in the condensing unit.
The simplest freezer evaporators have N, 3, 4, and X going to them. Should I have the electrician install a 3 pole switch breaking N, 3, and 4? I think that would work. Is there another good way to do it?
