mkernalcon
Member
Hi,
I'm currently most of the way done with my first experience with "Industrial Control Panel" building... quotes because, as you'll see, this thing barely counts as one. It also barely counts as PLC, so I wouldn't be offended if this is considered off-topic and you banned me. For background: I have plenty of electronics tinkering experience, I studied EE in college for a couple years (before I failed a circuits exam and immediately walked down to switch my major to Physics), and I have a ton of experience reading and interpreting building codes (IBC, NEC, etc.). However, I'm not an electrician or engineer, and the company I work for only deals with electricians as subcontractors (GC with a side of concrete/PEMB/OHD).
This project is an in-house, one-off system for integrating our private fuel pumps with our project management and financial systems (i.e. don't let guys get fuel until we know it's properly job-costed). I've attached a rough (but to-scale) drawing of the panel - the "PLC" in the top right is a Lenovo M75n IOT computer, with the "IOBOX" attachment on it (TBF it's programmable, and it controls logic - I just understand Linux and Python better than ladder logic, especially when I have to interface with SQL and a RESTful API). The power supply is a MW NDR-240-24. The relays are IDEC RL1N-D-D24 (flyback protection diodes not shown - I just wired some 1n4007's across the coil terminals. Yes I know that'll kill the relays sooner; good thing they're over-rated for the application). Also not shown are the door-mounted components: a 15" IP65 touch screen, and a panel-mount RFID reader. Besides the power wires for the monitor, I also have two USB cables, and a DP->DVI cable jumping that gap. There's also a panel-mount wifi antenna sticking out the top, wired to the computer. All field wiring will be done to the terminal blocks on the left.
This panel will control power to 1/3HP fuel pump motors, and receive input from pulsers (passive ones which just act like switches but require power, not active ones which actually pulse voltage). The software is set up so that only one pump will ever run at a time.
I've been attempting to follow UL 508A as close as possible, even though this will almost definitely never be evaluated as such. Seems like I'll just have to get it approved by an electrical inspector after it's installed, meaning NEC requirements.
In terms of shutoffs and surge protection, it's my understanding that I can get away without them on the actual panel, as long as: 1. there's a warning that this must be placed downstream of a dedicated 20A breaker, and 2. there's a warning that it must also be downstream of a dedicated emergency stop (which must be 20ft away), which is lockable open. We'll call in electricians to do the actual install. This is all 120VAC single-phase, and 24VDC (the power supply is self-protected, so that in the case of a dead short, it just stops outputting power). I'll be "rating" the panel at 5KA SCCR, and the available fault current does not exceed this.
The panel is pretty much built - I'm just waiting on a replacement IOBOX after the first one fried (I thought it was TVS protected well enough that I could leave out the flyback protection diodes, but the smoke proves otherwise).
SO: My remaining questions are mostly about labeling and documentation requirements that I don't quite understand, and I'd like to get right the first time.
First: terminal blocks and conductors. There are only 9 wires in the entire panel that are not L, N, Gnd, 24VDC or 0VDC. The three wires that go between the field wiring blocks and "D-IN" are for the pulser input - I'll likely label these as P1, P2 and P3 on both ends, and both sides of the t-blocks. The three wires between D-OUT and the relays I'll label R1, R2 and R3 on both sides. The three wires between the relay contacts and the terminal blocks are Line out to the pump motors - I'll label these M1, M2 and M3 on both ends and both sides of the t-blocks. Any problems so far? Also, how do you suggest labeling the connectors to the computer, for example - D-IN and D-OUT are tiny 2.5mm pitch pluggable terminal blocks. Can I just slap a label on the panel below the device?
For everything else (i.e. each remaining t-block connection and wire), can I just label these with the potential - i.e. I'd have 4 different wires and t-blocks that are labeled "L" on both sides? Or do I need to distinguish these? Also, for the 24VDC wires, since it seems I'm not allowed to use + or - on labels, does "0V" and "24V" make sense? I'd of course re-label the "V-" and "V+" that came printed on the PSU to match these.
As for the cables (USB, display, antenna), do I need to label these at all? And as for the barrel connector on the display for power, do I label the wires where they go into the connector, or the whole connector itself, or both?
...and before you mention it, yes I've followed the color-coding correctly. I even paid extra for the blue/white striped AWM, and one gauge bigger than I figured I needed on everything (12AWG for the 120V, 16AWG for the 24VDC). For t-block labels, I couldn't justify an actual printer, but I did pay for the $30 special Phoenix felt-tipped pen, and I promise to write neatly! I'll probably use the office Dymo for everything else.
Second: Panel Labeling. For sure, I know I need to put my company's name, and the SCCR on the panel somewhere. Looks like, for anything not already labelled as such, I need to put tightening torques on the panel. I will also put in a concise description of the external parts I assume in design (i.e. pumps 1/3HP each, the shutoff and circuit protection I expect, etc.). I'm a bit unclear on whether I need Arc Flash / Shock Hazard labels. Is there anything else I need?
Third: Documentation. Seems like I need to include a schematic diagram. Would the attachment count, if I added the missing components, added field wiring descriptions, and labelled everything? Or should I produce a more logical rather than physical schematic (this one was mostly to plan panel layout)? Is there anything else I ought to include with this?
Thanks so much for any help you can throw my way - I obviously need it. These forum archives have been a treasure trove of information, but on these specific issues, the questions that come up always seem to be about significantly more complicated situations, and I'm just an idiot trying to get the basics right.
TL;DR: I'm not an electrician, but I play one on TV. Please help me not make a complete fool of myself in front of the real electricians, or worse, the inspectors.
I'm currently most of the way done with my first experience with "Industrial Control Panel" building... quotes because, as you'll see, this thing barely counts as one. It also barely counts as PLC, so I wouldn't be offended if this is considered off-topic and you banned me. For background: I have plenty of electronics tinkering experience, I studied EE in college for a couple years (before I failed a circuits exam and immediately walked down to switch my major to Physics), and I have a ton of experience reading and interpreting building codes (IBC, NEC, etc.). However, I'm not an electrician or engineer, and the company I work for only deals with electricians as subcontractors (GC with a side of concrete/PEMB/OHD).
This project is an in-house, one-off system for integrating our private fuel pumps with our project management and financial systems (i.e. don't let guys get fuel until we know it's properly job-costed). I've attached a rough (but to-scale) drawing of the panel - the "PLC" in the top right is a Lenovo M75n IOT computer, with the "IOBOX" attachment on it (TBF it's programmable, and it controls logic - I just understand Linux and Python better than ladder logic, especially when I have to interface with SQL and a RESTful API). The power supply is a MW NDR-240-24. The relays are IDEC RL1N-D-D24 (flyback protection diodes not shown - I just wired some 1n4007's across the coil terminals. Yes I know that'll kill the relays sooner; good thing they're over-rated for the application). Also not shown are the door-mounted components: a 15" IP65 touch screen, and a panel-mount RFID reader. Besides the power wires for the monitor, I also have two USB cables, and a DP->DVI cable jumping that gap. There's also a panel-mount wifi antenna sticking out the top, wired to the computer. All field wiring will be done to the terminal blocks on the left.
This panel will control power to 1/3HP fuel pump motors, and receive input from pulsers (passive ones which just act like switches but require power, not active ones which actually pulse voltage). The software is set up so that only one pump will ever run at a time.
I've been attempting to follow UL 508A as close as possible, even though this will almost definitely never be evaluated as such. Seems like I'll just have to get it approved by an electrical inspector after it's installed, meaning NEC requirements.
In terms of shutoffs and surge protection, it's my understanding that I can get away without them on the actual panel, as long as: 1. there's a warning that this must be placed downstream of a dedicated 20A breaker, and 2. there's a warning that it must also be downstream of a dedicated emergency stop (which must be 20ft away), which is lockable open. We'll call in electricians to do the actual install. This is all 120VAC single-phase, and 24VDC (the power supply is self-protected, so that in the case of a dead short, it just stops outputting power). I'll be "rating" the panel at 5KA SCCR, and the available fault current does not exceed this.
The panel is pretty much built - I'm just waiting on a replacement IOBOX after the first one fried (I thought it was TVS protected well enough that I could leave out the flyback protection diodes, but the smoke proves otherwise).
SO: My remaining questions are mostly about labeling and documentation requirements that I don't quite understand, and I'd like to get right the first time.
First: terminal blocks and conductors. There are only 9 wires in the entire panel that are not L, N, Gnd, 24VDC or 0VDC. The three wires that go between the field wiring blocks and "D-IN" are for the pulser input - I'll likely label these as P1, P2 and P3 on both ends, and both sides of the t-blocks. The three wires between D-OUT and the relays I'll label R1, R2 and R3 on both sides. The three wires between the relay contacts and the terminal blocks are Line out to the pump motors - I'll label these M1, M2 and M3 on both ends and both sides of the t-blocks. Any problems so far? Also, how do you suggest labeling the connectors to the computer, for example - D-IN and D-OUT are tiny 2.5mm pitch pluggable terminal blocks. Can I just slap a label on the panel below the device?
For everything else (i.e. each remaining t-block connection and wire), can I just label these with the potential - i.e. I'd have 4 different wires and t-blocks that are labeled "L" on both sides? Or do I need to distinguish these? Also, for the 24VDC wires, since it seems I'm not allowed to use + or - on labels, does "0V" and "24V" make sense? I'd of course re-label the "V-" and "V+" that came printed on the PSU to match these.
As for the cables (USB, display, antenna), do I need to label these at all? And as for the barrel connector on the display for power, do I label the wires where they go into the connector, or the whole connector itself, or both?
...and before you mention it, yes I've followed the color-coding correctly. I even paid extra for the blue/white striped AWM, and one gauge bigger than I figured I needed on everything (12AWG for the 120V, 16AWG for the 24VDC). For t-block labels, I couldn't justify an actual printer, but I did pay for the $30 special Phoenix felt-tipped pen, and I promise to write neatly! I'll probably use the office Dymo for everything else.
Second: Panel Labeling. For sure, I know I need to put my company's name, and the SCCR on the panel somewhere. Looks like, for anything not already labelled as such, I need to put tightening torques on the panel. I will also put in a concise description of the external parts I assume in design (i.e. pumps 1/3HP each, the shutoff and circuit protection I expect, etc.). I'm a bit unclear on whether I need Arc Flash / Shock Hazard labels. Is there anything else I need?
Third: Documentation. Seems like I need to include a schematic diagram. Would the attachment count, if I added the missing components, added field wiring descriptions, and labelled everything? Or should I produce a more logical rather than physical schematic (this one was mostly to plan panel layout)? Is there anything else I ought to include with this?
Thanks so much for any help you can throw my way - I obviously need it. These forum archives have been a treasure trove of information, but on these specific issues, the questions that come up always seem to be about significantly more complicated situations, and I'm just an idiot trying to get the basics right.
TL;DR: I'm not an electrician, but I play one on TV. Please help me not make a complete fool of myself in front of the real electricians, or worse, the inspectors.
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