For panel buyers
UL 508A, explained for the people buying the panel
UL 508A is the standard for industrial control panels. Here is what certification under it covers, what it does not, what to look for on a certified panel, and how our shop works with UL.
What the certification covers
For an enclosed industrial control panel, UL describes the certification as covering the enclosure, the components inside it, and the components mounted on its walls. Open panels, without an enclosure, and enclosures on their own are certified as separate kinds of product.
It does not cover the equipment the panel controls. In UL's words, an industrial control panel "does not include the controlled loads, including motors, luminaires, heaters or utilization equipment." A machine or a robot that the panel runs has its own standards.
What the mark shows
A certified panel carries a UL certification mark with a file or control number. UL's current mark includes the UL symbol, the words "certified" and "safety", a geographic identifier and the file number; panels may also carry the earlier "listed" form of the mark with a control number. The product identity, such as "enclosed industrial control panel", appears on or near the mark.
Short-circuit current rating (SCCR)
The National Electrical Code (NFPA 70, 2023 edition, section 409.110) requires an industrial control panel to be marked with its short-circuit current rating, except a panel that contains only control-circuit components. Supplement SB of UL 508A gives a method for determining the rating from the panel's components. The rating has to be adequate for the fault current available where the panel is installed, so it helps to know that number when you ask for a quote.
When a panel isn't certified as an assembly
For equipment that does not carry an overall certification, UL notes that a field evaluation may be an option. Whether a field evaluation or a certified panel is needed is a question for the project and, where it applies, the local inspector.
How our shop works with UL 508A
- Gross Automation is a UL and cUL listed panel shop, UL File E239160: "Industrial Control Panels" (NITW) to UL 508A for the United States, and "Industrial Control Panels Certified for Canada" (NITW7) to CSA C22.2 No. 286. You can look the file up in UL Product iQ.
- Every panel the shop builds goes through its UL 508A program, and UL inspects the shop every quarter.
- Panels generally start from UL-certified components, and we help customers keep a design within UL 508A: component placement, and the fuse and breaker choices that set the SCCR.
- Repairs and modifications can be planned so a panel keeps its certification.
Questions to ask any panel shop
- Will this panel be built under your UL 508A program and carry the mark?
- How will the SCCR be determined, and what will it be?
- What enclosure rating suits the place the panel will live?
Sources: UL Solutions, "Does UL Certified Industrial Control Panel Certification Cover the Equipment It Controls?"; NFPA 70, National Electrical Code, 2023 edition, section 409.110 (the same marking requirement appears in earlier editions; check the edition your jurisdiction has adopted); UL 508A, Supplement SB. This page is general information, not a substitute for the standard or for your inspector's requirements.