Print plastic blank space fillers for the service panel


I'm guessing the answer is "no" but I saw this question and got curious. If panel fillers are expensive, and you don't have a breaker, can you 3d print your own? I'm guessing the panel front cover and fillers are part of UL and therefore making your own is against code?

Best Answer

You need to provide protection "substantially equivalent to the wall of the equipment..."

The governing NEC requirement for loadcenter "blank space" filler plates is in NEC 110.12(A):

(A) Unused Openings. Unused openings, other than those intended for the operation of equipment, those intended for mounting purposes, or those permitted as part of the design for listed equipment, shall be closed to afford protection substantially equivalent to the wall of the equipment. Where metallic plugs or plates are used with nonmetallic enclosures, they shall be recessed at least 6 mm (¼ in.) from the outer surface of the enclosure.

...which is much easier for a DIY to provide with sheet metal

This points us to what the wall of the equipment is required to provide, and that, in turn, is set out by NEC 312.10(B):

(B) Strength. The design and construction of enclosures within the scope of this article shall be such as to secure ample strength and rigidity. If constructed of sheet steel, the metal thickness shall not be less than 1.35 mm (0.053 in.) uncoated.

So, I'd use a piece of 16 gauge (or 1.6mm thick) sheet steel painted to match the existing cabinet, fastened with Garvin GSSTs (these are fairly short 10-32 self-drillers) in suitable places, as my "blank plate" if you couldn't find a manufacturer identified blank/filler and plugging the opening with breakers wasn't an option.