A slightly different control panel build

[shoo]

Built a control panel box for my hybrid RIMS/HERMS setup. Pretty happy with the way things turns out, and wanted to share a few things I learned along the way that I didn't see in other builds' DIY threads. This is a system which powers a single 1325W @120V RIMS tube, a chugger pump, and a 12v solar pump (system shown in this thread).

My panel is a bit different than others, in part because I built a few things in that aren't in the Kal build, most notably the electric auto-sparge and a safety switch for the heating element. Each of the float switch ports on the side panel goes to a float switch which either completes the circuit or doesn't (2 of the 3 XLR pins), which in turn triggers a relay. The MT one determines the level of water in the MT for sparging, where if the level is too low it triggers the chugger pump to pump more sparge water in. The RT one determines whethere there is water in my HLT above a set level. If not, it disables the element firing. I'll be switching that to a flow switch in the future.

One other limitation is that I was trying to save money, so a lot of this is built with scrap parts (most notably almost all the wiring, the enclosure, and the DC transformer).

On the other hand, I had access to a laser cutter, which was amazing. In addition to getting to laser etch some nice labeling (pro tip: etch it in mirror, and mount it flipped it over so the etched side touches the enclosure), but it also helped with one other thing: I also cut / etched drill guides as part of the panel build. The circles cut out for the switches for example, also had smaller circles in their centers, which I used to precisely center the pilot holes when drilling into my enclosure. That made life easier for sure.

As mentioned, almost of the wiring is scrap. In particular, one thing worth noting is that all of the super thin wire for low-power stuff (signals, relay coils, lights, and DC power) is 24AWG harvested from dead ethernet cables. Ethernet/cat5 cables are made up of 4 pairs of twisted 22-24AWG (i.e. 8 wires). One scrap ethernet cable gives you a LOT of wire to work with.

Also note: I haven't bothered to actually wire in fan control (turns out not necessary, as I am not generating that much heat) or the fuses. May do that eventually. Probably not.

But without further ado:

 

[BrunDog]

Pretty neat, especially the graphics and diagram in it.

It looks like you used CAT5 wire for the low voltage side. Next time, I would recommend stranded wire be used, as solid wire is prone to deformation/breakage. Not probable given the wires are not moving, but heat cycling and stress built in when wiring can pop up later and cause areas of increased resistance.

While typing, I would also recommend you add ring terminals, properly sized and crimped, to the SSR wires/posts.

 

[augiedoggy]

This reminds me of my original budget build in my avatar... I also used wire I had as well as the Harbor freight wire kit and repurposed relays from old xerox equipment.. Mine wasnt as neatly executed though..

I agree with the point above about non stranded wire it can be problematic in these types of applications. But being inside the panel it may be ok without any movement as well as the very low current used for temp sensing I dont think you will have heat issues there.. I dont know about the wire used elswhere like the contactor coils... I believe that needs more current than those 24awg wires can handle without heat.

 

[shoo]

Pretty neat, especially the graphics and diagram in it.

It looks like you used CAT5 wire for the low voltage side. Next time, I would recommend stranded wire be used, as solid wire is prone to deformation/breakage. Not probable given the wires are not moving, but heat cycling and stress built in when wiring can pop up later and cause areas of increased resistance.

While typing, I would also recommend you add ring terminals, properly sized and crimped, to the SSR wires/posts.

I may have just lucked out, but all of the wire I harvested from the Cat5 cables was stranded. I don't know if that's normal.

As for the adding ring terminals, absolutely will do. I was hesitating to make those permanent until I was 100% sure I got the wiring right, but now with 2 brew days under me with this panel I have some time to fix up a few points like that.

 

[shoo]

I dont know about the wire used elswhere like the contactor coils... I believe that needs more current than those 24awg wires can handle without heat.

Probably a good idea. I was also a bit concerned about that, and as a test I left it on with the coils activated over 24 hours. At the moment, the 24awg wires seem to be working fine to drive all the coils, and I haven't noticed any signs of heat in that test or in use. But I probably would recommend something beefier for those building something themselves.

The wire carrying the main and element-specific current is all 14awg to handle the nearly 15a draw with both the element firing and the chugger pump pumping, and is the only wire I actually had to purchase.

 

[augiedoggy]

Probably a good idea. I was also a bit concerned about that, and as a test I left it on with the coils activated over 24 hours. At the moment, the 24awg wires seem to be working fine to drive all the coils, and I haven't noticed any signs of heat in that test or in use. But I probably would recommend something beefier for those building something themselves.

The wire carrying the element current is all 14awg to handle the nearly 15a draw with both the element firing and the chugger pump pumping, and is the only wire I actually had to purchase.

its interesting that it appears you chose a 30a 240v connector for the 15a 120v rims? is this in case of future upgrades or did you have a change of plans? at 120v your only pulling like 5 amps I believe with the 5500w 240v element. I'm sure you know this but I'm just curious because you went with much larger contactors and plug than needed although im sure one is for your main power or do you have the pump and element power running through it as a safety??

 

[shoo]

its interesting that it appears you chose a 30a 240v connector for the 15a 120v rims? is this in case of future upgrades or did you have a change of plans?

I got lucky with the joys of scrapping. I managed to find a bunch of male connectors at a scrap shop for $0.50 each. I bought 5. The receptacle was the same cost either way, so I saved some $ overbuilding. Future upgrades which I currently have no plans for will appreciate it.

Similarly, the contactors were also the same price for 30a vs. 15a, so might as well get the 30a one.

Edit:

or do you have the pump and element power running through it as a safety??

Two giant contactors built in here. The first (left) is just the power switch, which kills everything (both hot and neutral, with ground always connected) going to the main bus (which is everything except the power switch itself, including the DC transformer and the pumps). The second big contactor is driven by the either the safety float switch (when in "auto" mode) or just by the switch itself ("bypass"). The hot side of the element is in series with the main contactor first, the safety switch contactor second, and the SSR last.

In theory, I draw about 11.5-12.5A from the element alone (120/110V, 1375W from a 5500W/240V element).