Created Date: October 27,2009

Created by: Bob S BN

I believe it is only for ambient air flow for cooling.

While I know it's not the right thing to do, I have retrifitted some in place of other PLCs with less than ideal space, and haven't had any trouble...YET..., knock on wood...

I imagine the space top to bottom would be more important than the sides.

Just my $.02

Created Date: October 27,2009

Created by: KPrice

dieseltwitch, well, it could be considered both NEC and UL code, and could be rejected upon inspection. While the NEC does not govern pre-built OEM control panels, the inspector could require either the panel to be built in a "listed " shop, or be inspected by a 3rd-party inspection agency. The "listed " shop or 3rd-party inspection would follow UL, and UL requires that the manufacturer's literature be followed in the installation and operation. The installation instructions is part of the component being UL listed.

So, yes, in a long, 'round-about-way, it is "NEC code, UL code, and MFG recommendation ". Hope this saves you some hassle.

Created Date: October 28,2009

Created by: Kristjan H

The space is mostly about cooling.

If you stuff the PLC in a tight place, you need to think of the PLC temperature. We have had some serious issues that we can't link to anything but heat buildup. The PLC was crammed in the cabinet and even though we had a ventilation fan on the cabinet it didn't provide much cooling. I measured over 50°C right above the PLC base and before long the analog modules started failing. We had more powerful ventilation installed to ensure cooling and right now the PLC temp is about 30-35°C. That makes a huge difference.