The RP1630C is a deep polycarbonate enclosure with a clear lid, 254 x 204 x 130 mm (10.00 x 8.03 x 5.12 in) overall. The transparent cover lets technicians check meters, displays and indicator LEDs, while 123.50 mm of inside height leaves space for bulky components and wiring.

The drawing describes the model as Polycarbonate Off-White with Clear Lid (UL94-V2); the part page lists the colour as Light Gray. The part page lists a nominal size of 250 x 200 x 130 mm (9.84 x 7.87 x 5.12 in); the ordering table and drawing give 254 x 204 x 130 mm (10.00 x 8.03 x 5.12 in) overall. The lid seals via a two piece tongue & groove joint with a field-installed rubber gasket, for an IP65 rating.

Inside dimensions are 241.70 x 192.20 x 123.50 mm (9.52 x 7.57 x 4.86 in). P.C. boards up to 235 x 186 mm mount on posts that accept M3 self-tapping screws, and internal DIN rail mounting tabs are part of the series design where size permits. The lid is secured with four self captivating M3.5 stainless steel screws into corrosion resistant bushings, torqued to 30-35 cN.m.

Packed in a bag with box, lid, string gasket, four PCB screws and four lid screws, the RP1630C has a shipping weight of 1.9 lbs (0.86 kg) and is RoHS and REACH compliant. Matching STC580 / STA580 inner panels and RP161GASKET are listed. Hammond notes that some chemicals, including acetone, ketones, thread locking compounds and cutting fluids, can damage or weaken plastic.