Thickness of Main LV Panel

[masalah]

The main Low Voltage Panel (LVP) that I mean here is the panel directly connected to the transformer LV side through ACB.

In the local specifications of the project which I'm working, the panel is specified to have a thickness of minimum 2mm for its frame steel sheet body.
The contractor proposed a material submittal of ABB manufacturing with a letter from ABB saying that its ArTuk panel having 1.5mm thickness is preserving the highest mechanical impact IK09 (glazed door) & IK10 (blind door).

My question is: why the specs. is requiring the 2mm thickness? If it's for mechanical impact only, so it's satisfied by the manufacturer letter.
But if there are other reasons (its explosion withstand for instance or any other thing), I may require another letter from the manufacturer to ensure preserving/fufilling these other reasons.

Thank you.

 

[jraef]

That answer can only come from whomever wrote that specification. But in general, sheet metal thickness in switchgear is typically used not simply for protection against external harm, but for rigidity and strength in withstanding the extreme mechanical forces involved in fault interruption, and on other cases, Arc Flash protection. It could be that your vendor has found a way to reinforce that rigidity and withstand capability by other mechanical means, such as bracing, added bending and such, but if you are also looking for any sort of Arc Flash protection, thinner is never better.

If it were me and Arc Flash protection was not an issue, I would be looking at the fault duty capability ratings more than the details of how they get there, and who certified those ratings. Here in North America we require 3rd parties, such as UL and CSA, to certify equipment. Elsewhere that may not be the case, and manufacturers are allowed to "self certify" their claims of meeting industry standards. You must decide for yourself whether to believe them or not. As a gross general rule, larger companies have more at risk (in terms of reputation at least) in making unreasonable decisions on construction methods, but bad decisions can come at any time when market pressures demand cost reductions, and you don't want to be the one who suffers from that before they reverse themselves.


"You measure the size of the accomplishment by the obstacles you had to overcome to reach your goals" -- Booker T. Washington

 

[ScottyUK]

Bear in mind that many of the IEC switchgear designs which are certified as internally arc classified actually achieve certification by virtue of it being 'impossible' to establish an arc due to copious use of moulded plastic shrouding. I also note that the Titanic was unsinkable, yet it lies at the bottom of the North Atlantic. I echo jraef's comment: thinner is rarely better.

 

[masalah]

Thank you very much for your replies. It really helped in my decision.

 

[wbd]

Thank you very much for your replies. It really helped in my decision.

and can you share that decision with the folks on this forum?

 

[masalah]

I refused the submittal requiring an official letter from the manufacturer to ensure that the thickness of 1.5 mm (which is less than that specified) will not only satisfy the mechanical impact protection degree of IK10, but also will have the sufficient rigidity and strength in withstanding the extreme mechanical forces involved in fault interruption, and/or arc Flash protection.