SAFETY WIRING for the LASER MACHINE, a GENERAL GUIDE Part 1 of TBD
Posted: Tue Dec 15, 2020
In a previous job I worked as an industrial electrician for battery manufacturing company and in that capacity I did a lot of machine controls trouble shooting, machine control design and wiring. The company followed strict industry safety standards for machine wiring. The machine operators were required to test guard switches, START/STOP and ESTOP switches at the beginning of every shift. This was our culture and we had very few accidents.
Many of the machines belonging to members of this forum do not have wiring that would meet typical industrial machine safety standards. Is this bad? Hard to say, each of us has a unique situation. In my case I am a sole proprietor, a trained laser safety officer, licensed electrician and the only one that uses the machine. I fully understand all of the hazards associated with my machine and operate it accordingly. Should I follow the advice I’m about to give you, absolutely! I figured that if I am going to make a stab at making my machine safer then I should share that information with the group. Some of you may have hired help or family members using the machine. In the event of an accident, how would you feel, in the case of an employee how will your insurance company react? I don’t think I need to explain the ramifications of any of this. I see a lot of haphazard YouTube videos that make me cringe.
When I ordered my machine (50W China Blue) I had already watched a number of Russ’s videos and because of that I purchased this over the K-40 which was my original plan. I had a pretty good idea of what I was getting and what I would need to do to make it safer to use. The day my machine was delivered I uncrated it and looked it over for damage. Next I got my ohm meter out and checked to see if the grounding was done correctly and to ensure all of the connections were tight. Overall wiring and grounding it looked pretty good with the exception that the paint needed to be removed where the ground wires attached to the metal cabinet and door. Yes the door, any door that has electrical devices installed in it and in this case a fan was attached to it. These should be bonded (grounded) to the rest of the machine because hinges do not make good grounds. With that said there were the expected issues with lack of safety wiring and this is what I want to address here.
The rules and standards for machine safety wiring are extensive, how it is accomplished, and very expensive. Anything I share here will not conform to such standards because the cost will be prohibitive for most of us. Many of us are hobbyists, one man/woman shops so this is a boiled down version to get something better than what we have for a price we can afford. If you chose to use this information do so at your own risk.
Many of our machines (I do not wish to single out any particular country of origin) as wired don't come close to meeting industrial machine safety standards. Below is a list in no particular order of electrical issues I noted on my machine. This may vary from machine to machine and they may have other issues not noted here.
1] ESTOP switch is wired in series with all things electrical on the machine. This switch is not designed to break the load of the machine in operation and the supplementary loads such as the air compressor or water pump.
2] No grounded receptacles for the water pump or air compressor. (120 volt USA Model)
3] No guard safety switch on the main lid.
4] AC wiring color code not correct for the USA market.
5] Air pump not grounded but did have a lug to attach a ground wire. The case of the machine had a grounding terminal where this could be attached. I attached a separate wire for this.
6] Paint not removed from the metal parts that have grounding/bonding conductors attached.
7] DC wiring color codes not typical for industrial machine wiring.
8] No wire numbers on conductors or electrical schematic.
9] The connections on the laser tube were not well done. I had arcing at the high voltage end between the tube and the cabinet which may have caused a gas leak at the terminal post and the early demise of my laser tube.
10] The machine is not listed nor did I expect it to be. That is to say this machine has not been evaluated by a nationally recognized testing laboratory for safety. This is a requirement in the USA and such labs could be UL, CSA, ETL, TÜV to name a few. Equipment that has been listed has undergone safety testing to ensure the end user is protected from hazards associated with the machine during operation. This requirement may be different in other countries.
These are some of the good things about the wiring on my machine.
1] Wires terminating in terminal strips all had crimped insulated wire ferules installed on the ends. Hot glue was applied to them where the wires terminated to prevent them from coming loose in shipping.
2] There were no wires just twisted together and wrapped with tape aka: “flying splices”.
3] The wiring was neat and easy to follow.
4] Soldered and slide on connections (mains voltage) had heat shrink tube installed at terminations.
Here are few questions to ask: What are the hazards we need to address? What kind of event(s) do you consider an emergency? Will pressing the stop button on the keypad solve the problem? Below is a short list of possible hazards.
1] A fire inside the machine
2] Material moved out of position
3] Laser head crashed into something
4] Job is not running as expected
5] Guard door opened
6] Add something else to this list
I have a plan for how I want my machine to work which I will share but at this point I’m going to stop here and see what kind of discussion we get on this topic. I certainly welcome any questions, comments, and suggestions.
Many of the machines belonging to members of this forum do not have wiring that would meet typical industrial machine safety standards. Is this bad? Hard to say, each of us has a unique situation. In my case I am a sole proprietor, a trained laser safety officer, licensed electrician and the only one that uses the machine. I fully understand all of the hazards associated with my machine and operate it accordingly. Should I follow the advice I’m about to give you, absolutely! I figured that if I am going to make a stab at making my machine safer then I should share that information with the group. Some of you may have hired help or family members using the machine. In the event of an accident, how would you feel, in the case of an employee how will your insurance company react? I don’t think I need to explain the ramifications of any of this. I see a lot of haphazard YouTube videos that make me cringe.
When I ordered my machine (50W China Blue) I had already watched a number of Russ’s videos and because of that I purchased this over the K-40 which was my original plan. I had a pretty good idea of what I was getting and what I would need to do to make it safer to use. The day my machine was delivered I uncrated it and looked it over for damage. Next I got my ohm meter out and checked to see if the grounding was done correctly and to ensure all of the connections were tight. Overall wiring and grounding it looked pretty good with the exception that the paint needed to be removed where the ground wires attached to the metal cabinet and door. Yes the door, any door that has electrical devices installed in it and in this case a fan was attached to it. These should be bonded (grounded) to the rest of the machine because hinges do not make good grounds. With that said there were the expected issues with lack of safety wiring and this is what I want to address here.
The rules and standards for machine safety wiring are extensive, how it is accomplished, and very expensive. Anything I share here will not conform to such standards because the cost will be prohibitive for most of us. Many of us are hobbyists, one man/woman shops so this is a boiled down version to get something better than what we have for a price we can afford. If you chose to use this information do so at your own risk.
Many of our machines (I do not wish to single out any particular country of origin) as wired don't come close to meeting industrial machine safety standards. Below is a list in no particular order of electrical issues I noted on my machine. This may vary from machine to machine and they may have other issues not noted here.
1] ESTOP switch is wired in series with all things electrical on the machine. This switch is not designed to break the load of the machine in operation and the supplementary loads such as the air compressor or water pump.
2] No grounded receptacles for the water pump or air compressor. (120 volt USA Model)
3] No guard safety switch on the main lid.
4] AC wiring color code not correct for the USA market.
5] Air pump not grounded but did have a lug to attach a ground wire. The case of the machine had a grounding terminal where this could be attached. I attached a separate wire for this.
6] Paint not removed from the metal parts that have grounding/bonding conductors attached.
7] DC wiring color codes not typical for industrial machine wiring.
8] No wire numbers on conductors or electrical schematic.
9] The connections on the laser tube were not well done. I had arcing at the high voltage end between the tube and the cabinet which may have caused a gas leak at the terminal post and the early demise of my laser tube.
10] The machine is not listed nor did I expect it to be. That is to say this machine has not been evaluated by a nationally recognized testing laboratory for safety. This is a requirement in the USA and such labs could be UL, CSA, ETL, TÜV to name a few. Equipment that has been listed has undergone safety testing to ensure the end user is protected from hazards associated with the machine during operation. This requirement may be different in other countries.
These are some of the good things about the wiring on my machine.
1] Wires terminating in terminal strips all had crimped insulated wire ferules installed on the ends. Hot glue was applied to them where the wires terminated to prevent them from coming loose in shipping.
2] There were no wires just twisted together and wrapped with tape aka: “flying splices”.
3] The wiring was neat and easy to follow.
4] Soldered and slide on connections (mains voltage) had heat shrink tube installed at terminations.
Here are few questions to ask: What are the hazards we need to address? What kind of event(s) do you consider an emergency? Will pressing the stop button on the keypad solve the problem? Below is a short list of possible hazards.
1] A fire inside the machine
2] Material moved out of position
3] Laser head crashed into something
4] Job is not running as expected
5] Guard door opened
6] Add something else to this list
I have a plan for how I want my machine to work which I will share but at this point I’m going to stop here and see what kind of discussion we get on this topic. I certainly welcome any questions, comments, and suggestions.
