My company is persistent on the reason why a industrial computer instead of a regular computer (home use) cannot be in a control cabinet with 460V power. I tell them that it has to be Nema Rated but they don't take that as an answer. Can anybody point me to the code on this?
Computer equipment in Control Cabinets
- Thread starter dirishone
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Re: Computer equipment in Control Cabinets
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My company is persistent on the reason why a industrial computer instead of a regular computer (home use) cannot be in a control cabinet with 460V power. *********************
I'm not sure I understand your question as stated, but industrial computers normally have higher temperature ratings, provisions for dealing with high vibration, hold-down brackets for cards, etc.
Usually the only thing NEMA rated is the keyboard & mouse and a panel-mount monitor that is NEMA rated.
I don't see anything wrong with using a "normal" PC in a control panel as long as the enviroment in the panel is OK (temperature & vibration.
Industrial computers cost so much more that many companies are using "normal" PC's and taking the savings to buy a spare one to have on hand it fails.
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My company is persistent on the reason why a industrial computer instead of a regular computer (home use) cannot be in a control cabinet with 460V power. *********************
I'm not sure I understand your question as stated, but industrial computers normally have higher temperature ratings, provisions for dealing with high vibration, hold-down brackets for cards, etc.
Usually the only thing NEMA rated is the keyboard & mouse and a panel-mount monitor that is NEMA rated.
I don't see anything wrong with using a "normal" PC in a control panel as long as the enviroment in the panel is OK (temperature & vibration.
Industrial computers cost so much more that many companies are using "normal" PC's and taking the savings to buy a spare one to have on hand it fails.
Re: Computer equipment in Control Cabinets
Equipment must be approved for its use.
110.2 Approval.The conductors and equipment required or permitted by this Code shall be acceptable only if approved.
110.3 Examination, Identification, Installation, and Use of Equipment.(B) Installation and Use. Listed or labeled equipment shall be installed and used in accordance with any instructions included in the listing or labeling.
PC (home computers) are not listed for use in control cabnets.
Equipment must be approved for its use.
110.2 Approval.The conductors and equipment required or permitted by this Code shall be acceptable only if approved.
110.3 Examination, Identification, Installation, and Use of Equipment.(B) Installation and Use. Listed or labeled equipment shall be installed and used in accordance with any instructions included in the listing or labeling.
PC (home computers) are not listed for use in control cabnets.
Re: Computer equipment in Control Cabinets
Jerry, although I understand your intent, please read the definition of "Approved". The approval status could be determined by the applicable AHJ. This could be an engineer giving his blessing to using a "home use" PC.
AS far as 110.3
Roger
Jerry, although I understand your intent, please read the definition of "Approved". The approval status could be determined by the applicable AHJ. This could be an engineer giving his blessing to using a "home use" PC.
AS far as 110.3
if the instructions don't prohibit the questionable use, then we may not be violating anything.
Roger
Re: Computer equipment in Control Cabinets
Roger, I do respect your opinion and the definitions are correct. However, as an electrical inspector, I cannot arbitrarily approve something. Approval must be based on this Code (90.7 Examination of Equipment for Safety, 110.3 Examination, Identification, Installation, and Use of Equipment, etc.) product listing and labeling and manufactures instructions.
As a control systems engineer for twelve years, I had to use the same criteria as above but was subject to the AHJ judgment. An engineer is not an AHJ and cannot give his blessing to use equipment not listed for the purpose.
As for your second definition, again you are completely correct with the definition, however, the UL white book (General Information for Electrical Equipment) states what things can be used for in the positive rather then in the negative. If equipment is not classified NIMX (Industrial Control Equipment) then it cannot be used for industrial equipment.
Article 670 Industrial Machinery refers you to NFPA 79 Electrical Standard for Industrial Machinery that goes into more detail on Industrial Control Equipment usage.
PS. The manual for my computer states ?is intended for home or other limited viewing use only? thus precluding industrial control usage.
Jerry
Roger, I do respect your opinion and the definitions are correct. However, as an electrical inspector, I cannot arbitrarily approve something. Approval must be based on this Code (90.7 Examination of Equipment for Safety, 110.3 Examination, Identification, Installation, and Use of Equipment, etc.) product listing and labeling and manufactures instructions.
As a control systems engineer for twelve years, I had to use the same criteria as above but was subject to the AHJ judgment. An engineer is not an AHJ and cannot give his blessing to use equipment not listed for the purpose.
As for your second definition, again you are completely correct with the definition, however, the UL white book (General Information for Electrical Equipment) states what things can be used for in the positive rather then in the negative. If equipment is not classified NIMX (Industrial Control Equipment) then it cannot be used for industrial equipment.
Article 670 Industrial Machinery refers you to NFPA 79 Electrical Standard for Industrial Machinery that goes into more detail on Industrial Control Equipment usage.
PS. The manual for my computer states ?is intended for home or other limited viewing use only? thus precluding industrial control usage.
Jerry
jerod
Member
- Location
- California
Re: Computer equipment in Control Cabinets
thanks for joining jerry and don't be shy. sounds like we can use your background.
thanks for joining jerry and don't be shy. sounds like we can use your background.
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: Computer equipment in Control Cabinets
I think that the listing is for processes that would put persons in danger of injury upon failure of the computer. industrial computers have dust and moisture and vibration protection as well as surge protection built in to it. but most home computers would not last long in these circumstances. and depending on the process that it might control could cause injury to someone if it went hay-wire. what if it caused a shear to run when it wasn't suppose to?. what about an office environment? could a AHJ tag a computer in an office if the listing says home use only?
I think that 90.4 gives the AHJ the ability to allow this if there is no breach of safety. like a computer that just logs operations or product runs and doesn't have any thing to do with the machinery.
I think that the listing is for processes that would put persons in danger of injury upon failure of the computer. industrial computers have dust and moisture and vibration protection as well as surge protection built in to it. but most home computers would not last long in these circumstances. and depending on the process that it might control could cause injury to someone if it went hay-wire. what if it caused a shear to run when it wasn't suppose to?. what about an office environment? could a AHJ tag a computer in an office if the listing says home use only?
I think that 90.4 gives the AHJ the ability to allow this if there is no breach of safety. like a computer that just logs operations or product runs and doesn't have any thing to do with the machinery.
Re: Computer equipment in Control Cabinets
Jerry, first of all, thank you for the respect.
Now, I don't understand what you mean by "arbitrarily approve something".
As an inspector you would have the substance i.e. training, knowledge, expertise, experience, etc... to remove the word "arbitrarily.
If you "examined" an item and deemed it safe with the above mentioned qualifications under your belt, what else would you need?
Please don't tell me you are misunderstanding 90.7 and 110.3 to mean everything must be third party tested.
Let's look at the issue at hand,a PC being plugged into a receptacle inside a cabinet in an industrial setting. Do you as an inspector look at all cord and plug connected equipment in a facility? This would mean checking radios, clocks, portable lamps, etc...
It seems to me this would truly be an issue under "supervised engineering", and the "supervising engineer" would be the AHJ in this matter.
Roger
Jerry, first of all, thank you for the respect.
Now, I don't understand what you mean by "arbitrarily approve something".
As an inspector you would have the substance i.e. training, knowledge, expertise, experience, etc... to remove the word "arbitrarily.
If you "examined" an item and deemed it safe with the above mentioned qualifications under your belt, what else would you need?
Please don't tell me you are misunderstanding 90.7 and 110.3 to mean everything must be third party tested.
Let's look at the issue at hand,a PC being plugged into a receptacle inside a cabinet in an industrial setting. Do you as an inspector look at all cord and plug connected equipment in a facility? This would mean checking radios, clocks, portable lamps, etc...
It seems to me this would truly be an issue under "supervised engineering", and the "supervising engineer" would be the AHJ in this matter.
Roger
Re: Computer equipment in Control Cabinets
Roger, I think if you reread my posting you will see I said ?I cannot arbitrarily approve something? making the next two points moot.
Also, the original posting said ?in a control cabinet with 460V power? it did not say in a facility. So as an inspector, I would not check all the plug connected equipment in a facility. I would however, check all the plug connected equipment in a 460 volt control cabinet if that was what I was required to inspect.
The original posting asked ?Can anybody point me to the code on this?? This thread has gone beyond that and hurk27 made an excellent point that industrial computers are more robust then PC?s both inside and out; they are designed to fail in a safe mode if programmed correctly. Industrial computer are designed for control applications while PC?s are designed for data applications.
PS My hp pavilion is truly a home computer and the manual states, ?is intended for home or other limited viewing use only?. So it can be used in a home as well as an office or a factory for viewing data but not for controlling. :roll:
Jerry
Roger, I think if you reread my posting you will see I said ?I cannot arbitrarily approve something? making the next two points moot.
Also, the original posting said ?in a control cabinet with 460V power? it did not say in a facility. So as an inspector, I would not check all the plug connected equipment in a facility. I would however, check all the plug connected equipment in a 460 volt control cabinet if that was what I was required to inspect.
The original posting asked ?Can anybody point me to the code on this?? This thread has gone beyond that and hurk27 made an excellent point that industrial computers are more robust then PC?s both inside and out; they are designed to fail in a safe mode if programmed correctly. Industrial computer are designed for control applications while PC?s are designed for data applications.
PS My hp pavilion is truly a home computer and the manual states, ?is intended for home or other limited viewing use only?. So it can be used in a home as well as an office or a factory for viewing data but not for controlling. :roll:
Jerry
Re: Computer equipment in Control Cabinets
Hello Jerry. I appologize for being rude, Welcome to the forum.
Now let's go to what you said,
Roger
Hello Jerry. I appologize for being rude, Welcome to the forum.
Now let's go to what you said,
not really. The truth is, there is no issue as far as the NEC in this installation. If I were building this cabinet I would bring all hard wiring methods to the cabinet make the terminations and have it inspected. (your extent of the process)
Roger
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
Re: Computer equipment in Control Cabinets
It this is a UL 408 Industrial Motor Control application , then it would be OK if included in the listing process. I suspect that some industrial computers are a recognized component and could be UL 508 listed. Home computers would not be so listed due to the cost. A call to a UL 508 shop would get you some advice..
It this is a UL 408 Industrial Motor Control application , then it would be OK if included in the listing process. I suspect that some industrial computers are a recognized component and could be UL 508 listed. Home computers would not be so listed due to the cost. A call to a UL 508 shop would get you some advice..
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