@Jon Okay. So are we a go for 3 20A next to tarkin, 2 20A near pearl, (1 20A in the middle if we have enough wire) Plus an extra drop in the “closet” for the blowers?
Zackg- I see what supply you were looking at. That is one of the two. It’s potentially 20A if you were to draw all its capacity, but we will not have such a load. The equipment on it will draw ~2KW off each supply which is about 11A input. That’s both a sustained load and the max, there’s no peak worst-case above that.
Pearl’s chiller actually does have a 10A nameplate power draw. I don’t see how it could draw that much for its size, I think they were generously overstating it, but we can see. It matters only in the case of trying to run Pearl’s 10A along with a 10A chiller across one 208V circuit would not work with 20A capacity. But if we’re talking two drops, it won’t matter.
Yep I know the failure modes in using 3 phase this way. It’s a legitimate configuration, but not super easy to understand what’s going on. The two supplies places on the delta sides WX and XY and nothing on the YW side results in currents of 11A, 17A, and 11A if I did that right (and I’m not 100% sure I did). So, the middle conductor would be kind of close for a 3ph too at 20A.
Running Tarkin off two independent 20A 208v circuits sounds pretty strange, but, OK, the system can work this way. If you want to run it that way it’s ok by me, I just want power to work on get it up and running rather than go back and forth forever on that part.
These don’t use a neutral, so 12/2+ground is approp for all these.
I think you’ve underestimated the blowers though. The ones we use right now are closer to 750W, and we could still use more flow. And I think that black 500W blower I have near Tarkin is probably going to be underpowered. I’m saying two 20A phases plus neutral for this would be flexible if this comes up like I think it will.
We can relay-control these of course with low voltage relays, still great with that.
My thought is to power each one of the 2 laser power supplies with it’s own 20A drop. This will avoid needing to buy any 10g wire. Then Tarkin’s chiller is a 3rd 20A, and this is I’ve listed a total of 3 drops for tarkin. Each drop will be on it’s own circuit. Plus we’ll be able to juggle equipment in the room as needed, since they are all powered the same way.
The blowers will be on a single 20A 110v drop, totally separate. Each of those is a 500w blower, so a 20a circuit should work just fine.
OK, as trivial as a relay is, any ideas on getting that physically inline with the blowers’ power cords? We could make pigtail cords with the hot coming out and the relay, like, taped to the cord for support. But there’s probably a better way.
These would do the trick nicely Controllable Four Outlet Power Relay Module version 2 [(Power Switch Tail Alternative)] : ID 2935 : $29.95 : Adafruit Industries, Unique & fun DIY electronics and kits I found a few other off-the-shelf options but they’re weirdly expensive. For $30 apiece it’s probably not worth the time to try building our own in an enclosure.
Assuming the laser call for exhaust is just a contact closure, we’d also need something like a doorbell transformer to supply control voltage.
If we have any controllers that lack an exhaust contact, we could probably retrofit with a current-sensing relay eg Veris Hawkeye H800 | Current Switches | EnergyControl.com.
@EricP Here’s the shopping list for Amazon.
6x ELEGRP NEMA L6-20R Flush Mounting Locking Receptacle, Twist Lock Socket/Outlet for Generator, 20 Amp 250V 2 Pole 3 Wire Grounding, Industrial Grade Heavy Duty, UL Listed (1 Pack, Black): Amazon.com: Tools & Home Improvement
6x Leviton SL721 C-Series 1-Gang Single 1.6-inch Diameter Opening Wallplate, Type 430 Stainless Steel - - Amazon.com
2x (to be hacked up as inputs cables for Tarkin) Amazon.com: Tripp Lite Heavy-Duty Power Cord for PDU and UPS 20A, 12AWG (IEC-320-C19 to NEMA L6-20P) 6-ft.(P040-006) Black : Everything Else
1x (To replace the plug on pearl) https://www.amazon.com/L6-20P-Connector-Locking-Industrial-Twist-Lock/dp/B07R4CMVTK/
4x Square D by Schneider Electric QO220CP QO 20Amp Two-Pole Circuit Breaker - - Amazon.com
Do we really have QO panels? the existing breakers didn’t look familiar to me
I had the same thought a s @Jon - I don’t think that’s the right panel style.
But the breaker for Tarkin should be 3 pole anyways, right? If you use two pole, and it has two plugs, then there’s a possibility that you can cut power to one part but not another. This is one reason I preferred a 3 phase situation all the way down- it seems like a safety risk to be running two circuits to the same machine.
But does code even allow the alternative? To run two phases of a breaker to different 12/2 runs as one of their hots, then the other hot of each 12/2 is tied together as the third phase of the breaker?
Hmm… that actually brings back the prob that the phase that gets used twice sees an estimated 17 amps. When split across two 20A runs, the ampacity of the combined wiring is fine, each sees ~11 amps. But when joined at the breaker the vector sum of two 11A loads 120 deg off from each other is still 17A, which is close to the breaker’s trip point.
@Jon QO breakers fit in a bunch of different style panels. I believe that’s a QO-style panel, but if they are the wrong ones, the electrician will switch them out. He has a large collection, and uses 20A QO’s frequently. Order those and we should be set.
@dannym Since we have 2 different power supplies to power… to break it down from 3 phase to 2 208’s requires extra hardware inside of Tarkin to be done to code. Each of those PSUs needs to have a 20A or smaller breaker in front of it. You can’t directly feed the 30A into those PSUs. Plus acquiring the correct wire. As I said, this is a simple solution.
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I spent a few hours there and got the wires pulled. We need to go through and find 2 more breakers we can shut off, since we’re going for 2 blower circuits. I counted 12 breakers that were off, we need 14. There’s one for the kitchen water heater… Is that still in use?
I spoke with Carl and he says he’ll probably be by Monday to finish the work out if nothing pops up. Ya’ll were both right, that’s a GE panel, not QO. Carl said he will swap out whatever we have for the right ones.
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I’m pretty sure “kitchen water heater” is the one on the little bar sink – if so, it’s still in use.
Whichever air handler breaker isn’t connected to an air handler anymore can be replaced – in addition to the “condenser” breaker, there’s both “Air Handler” and “AHU” and I’m pretty sure only one of the latter is in use
Thanks!
Saving breaker slots was part of the case for 3 phase, and/or more amperage. Running 3 phase is 3 slots. Two 208v circuits takes 4 slots. One 30A or larger run instead of 2x 20A runs takes 2 slots instead of 4x.
There’s also the 2+neutral for 208v plus neutral which can be 208v and 120v that would take up only 2 slots, but that one is a little dreaded for… reasons, but still legit to use and good for saving slots.
The water heater is definitely in use.
There are 2x 100A 3ph breakers and a couple of singles labeled “dead”, those should be unconnected to anything.
Additionally, there are unlabeled breakers. Slot #23 is unlabeled and has been off forever, but I don’t know if it goes to any wiring or not. Also Slot #4 just has a label “?” and I don’t know.
There are some unused nonstandard outlets on the north wall of the lounge. I don’t recall if they’re 220V power outlets or what but not 120VAC, nor what panel they’re on- if they’re even power outlets to begin with.
“RT COMP” is the air conditioning rooftop compressor. “AIR HANDLER” and “LOUNGE AHU” do sort of mean the same thing so I’m not sure why there are both. It could be that the 208V 30A one is the handler, and the 208V 60A is Emergency Heat inside the handler, in addition to the compressor? I don’t know.
Sorry to back up, but I don’t follow this. While the PSUs are rated for 20A each, there is no such load. They’re 11A each for a 22A load. It’s legitimate to use a 30A feed as long as the outlet is a 30A NEMA type.
A 15A outlet does not require a power cord with 15A to be plugged into it. Christmas lights are like 5 amp wires. The PSU’s configuration can only draw 22A combined, and could only exceed it under a fault condition, such as the power supply failing and shorting out, which is what the breaker is for.
Also (again, apologies for backing up) running 3 ph for Tarkin and/or chiller is a legit config as long as the vector sum on the phases is correctly calculated. That would be an “open wye”:
That does allow for a single 3 ph maintenance lockout, and/or also a single power cord that could be unplugged for maintenance.
It’s legitimate to use a 30A feed as long as the outlet is a 30A NEMA type.
No it’s not. That’s where there’s confusion. You’re missing failure cases.
When you change the amperage of a circuit, you have to have the correct overcurrent protection in place for the sub-device(s). Most 3 phase equipment has a series of breakers or fuses in them for doing just this. The PSU is rated for taking in 20A. Yes it’ll function if you plug it into a 100A circuit, but it won’t have the correct overcurrent protection. If there’s a short in the PSU that causing a continuous 25A draw, and the PSU is not designed for dissipating that kind of heat, it’ll catch fire without tripping the 30A breaker in this case. (This is why I said all the failure cases are complex).
Christmas lights are like 5 amp wires.
And in the non-LED ones, there’s a little fuse in the plug to provide over-current protection for the wire.
running 3 ph for Tarkin and/or chiller is a legit config
Yes, you could hook it up as 3 phase, yes. Not arguing that. It’ll function. But does it have correct overcurrent protection, and is it cost effective to setup (see the bottom of this about cost)? In the doc you linked, it’s listed as a non-standard configuration. Probably for the reasons I’ve listed.
That does allow for a single 3 ph maintenance lockout, and/or also a single power cord that could be unplugged for maintenance.
That would be nice, yes. But not all equipment has a single disconnect. Large AC systems often have multiple disconnects. Even ones in a house can. If you have an electric furnace, then you’ll have one 220v for the heat, and a 110v for the blower. You have to shut off both to kill power to your indoor unit.
Part of this also cost based. 2 runs of 12/2+g is cheaper than 10/3+g. I just pulled up lowes, and 10/3+g AC is $1.59/ft, 12/2+g AC is $0.62/ft. So you can make 2 12/2 runs for less then the price of 1 10/3 run. And it’s easier to physically run. And it makes use of the wire we already have. Unless the appliance has all the pre-wire for 3phase, it’s just not worth setting up.
The electrician can through and did part of the wiring. They’ll complete it another day.
I looked through the supplies, we still need 1 more: https://www.amazon.com/L6-20P-Connector-Locking-Industrial-Twist-Lock/dp/B07R4CMVTK/
Plus tarkin needs 2 power cables. I think these would work: Amazon.com: Tripp Lite Heavy-Duty Power Cord for PDU and UPS 20A, 12AWG (IEC-320-C19 to NEMA L6-20P) 6-ft.(P040-006) Black : Everything Else
Edit: I mentioned these two items earlier. I just don’t know if they’ve arrived yet or not.
@zackg awesome!
@Eric are we waiting for any more parts to arrive?
I’m pretty sure I have an L6-20P in my box-o-parts if we just need one more. I definitely don’t have 3.
The power cords have not been delivered yet they are on the way. Dont have another L6-20P on order.
@zackg @Jon
Great! What do we have running to the fan area now, and what plug does it end in?