Control Panel Standards?

[carlosgw]

I wanted to sneak in here from another discipline. I was wondering if there were accepted standards for control panel design, materials, assembly? (esp. design)
I get involved with temperature control and HVAC equipment control panels now and again.

Second related question - how does a panel shop become a UL panel shop?

 

[jraef]

UL.com will answer both questions

"Venditori de oleum-vipera non vigere excordis populi"

 

[buzzp]

You want UL508A, as far as standards. Lots of info on their website with regards to becoming a UL listed panel shop.

 

[EEIre]

In IEC countries look at IEC60947 and 60439.

Regards

Sean

 

[jsummerfield]

What is the application? How many standards are of interest?

If anything is electrical comply with the NEC or appropriate international electrical code.

Does anything require environmental protection or corrosion resistance, perhaps compliant with a NEMA or IEC rating or salt spray test such as ASTM B117?

Standards exist for the sheet metal thickness and stainless steel finishes such as ASTM A 480.

Are there issues pertaining to the electrical area classification? Is intrinsically safe equipment connected?

Is this a pneumatic or hydraulic panel, associated with the food or offshore platform business? The requirements differ.

Is it indoors in a building or outdoors in the open? Perhaps surge withstand issues exist.

ISA has some old standards pertaining to control room panels for centralized process control. One that is still useful helps to clarify the corrosiveness of the area. Low levels of H2S can eat copper on printed circuits.

I do not worry much about UL standards. In some regions a “Union Label” is essential but not where I work.

The Federal Register and many standards can apply to the human engineering or ergonometric issues. Perhaps some reports from the Three-Mile Island debacle are applicable.


John

 

[carlosgw]

Thanks for the info.
Anything I would likely get involved in would be HVAC related, no special locations.
An example was a panel I had to come up with for a speciallized air conditioner. It was pretty simple with some contactors, a SCR power controller and control relays. It had a power supply. (the actual control came from a separate panel with a PID controller)
I can't remember all the questions I had at the time but are there standards for things like conductor size/insulation, power supply/fusing, terminations, etc? Or is it more of a common sense, experience kind of thing?

 

[brinkmann27]

Common sense is good but, use UL 508A and the N.E.C. for sizing of conductors, contactors, fuses, etc.

 

[minder]

In N.America there is the NFPA79 'Electrical Standards for Industrial Machinery', copies can be obtained from the NFPA site.
M.

 

[carlosgw]

Thanks for the info. I have not had time or need to follow up anything, but I just picked up the new (2005) NEC and noticed the new article 409.

 

[zonecontroller]

FYI.

In the UK, there are 3 specific standards relating to the design, build and testing of electrical control panels for machinery and environmental (HVAC) control systems.

1. BS60204. Industrial Control Equipment. (For design and testing detail of the panel itself.)

2. BS7671. Electrical Installation Regulations. (For how to choose conductors, protective devices, etc.)

3. BS60947. Industrial Control Equipment. (All components, relays, controllers, switchgear, etc should be built to this standard. And this equipment will be installed on your panel backplate.)

With these three standards you can build a CE approved control panel, and we use this in the UK for HVAC, DDC and BMS panels too.

Atop this, there are 2 other relevant standards, the Ingress Protection Rating (IP2x - IP6x), where an indoor panel would be say IP54. And Form Factor, where form 2 would be seprate Power and Control sections, and Form 4 would be a cubiclised panel, where any single starter section can be isolated without affecting any other starter in the panel, for example.

 

[ray2625]

Following artical 409 is a good start, it will point you in the right direction. Not all the states have adopted the latest NEC version, there are a number still following NEC2002 and older. Article 409 is a new section to address industrial power controls and basically pulls together all those power related items into one section making it easier to follow.

 

[jraef]

The NEC has been generally used for standards relating to the installation of equipment, not necessarilly the internal construction of an assembly already listed by a NRTL such as UL. It appears from these comments that I need to look at this article 409 to see how that relates since it sounds as though the NEC is bleeding over into internal construction details. is this in the 2005 version? It isn't in 2002.

"Our virtues and our failings are inseparable, like force and matter. When they separate, man is no more."
Nikola Tesla

 

[jraef]

Never mind, answered my own question. It is new in the 2005 NEC. Guess it's time to break out the credit card...