Enclosure access

[Bestme]

Hi Everyone,
I know enclosure access is always a confusing topic. I'm looking at what guards are required on a 480 fed control panel. It houses servo amplifiers and PLCs.
The enclosure has a sequester box, where 480 can be disconnected with a lockable, rotary style disconnect. The 480 then runs from the sequester box into the main control cabinets (6' tall, single door cabinets).
The guarding on the doors is such that a key or tool is required to open the cabinets at all time, underload or not.
However, the door does not automatically latch if closed. Additionally, nothing prevents you from turning the power on if have a cabinet door open.

I believe this is a violation due to section 66.1.5.1
66.1.5.1 The interlocking means required by 66.1.5 shall be provided with all the following:
a) Means to defeat the interlock without removing power and which requires the use of a tool to
operate;
b) Means to prevent restoring power while the enclosure doors are open unless a defeat
mechanism is operated; and
c) Reactivated automatically when all the doors are closed.

Please advise. The OEM is saying this is how they've always done it and they have never been questioned.

Kind Regards and Thanks in Advance!

 

[Bestme]

I think I've answered my own question. Siemens spells it out pretty clearly in this reference manual:

https://assets.new.siemens.com/siemens/assets/api/uuid:6826bcbd-f0a9-476b-bef9-9ab23763f167/controlpanelna-guideline-icp-us.pdf

" UL 508A describes the industrial control panel from the supply terminal to the outgoing terminals into the field (field wiring terminals). Areas outside the industrial control panel are no longer described in UL 508A. On the other hand, NFPA 79 describes the entire machine. This includes possible subdistribution boards that may be supplied by a main panel with a disconnecting means. Chapter 6.2.4 of NFPA 79 regulates this topic as follows: If a qualified person opens an industrial control panel enclosure that does not have its own disconnecting means under voltage, one of the following conditions shall be met:
1. The use of a key or tool shall be required for opening the industrial control panel door.
2. An enclosure door shall be permitted to be opened without the use of a key or tool only when all live parts inside are separately enclosed or guarded such that there cannot be any direct contact with live parts."