Centaur Round Plastic Nail-On ...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$388.80
Centaur Round Plastic Nail-On Electrical Box - 20 cu in (per 75)

Centaur Round Plastic Nail-On Electrical Box - 20 cu in (per 75)

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Model: TAMCO-PSBR20

In Stock (leaves warehouse same day if ordered before 3pm ET)

$388.80
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Centaur 3" Round Plastic Switch & Ceiling Boxes – 20 Cu. In.

These 3-inch round plastic boxes from Centaur are designed for efficient and code-compliant installations of lighting fixtures, ceiling fans, or other round-device applications in new construction settings. Each box is constructed from non-metallic, flame-retardant thermoplastic that resists impact and corrosion. With multiple configuration options, including models with grounding clips, bar hangers, and color-coded designs, these boxes offer flexibility and ease of installation.

SKU Width Height Diameter Weight
PSBR20-BHA 18.25 Inches 4 Inches 4 Inches 0.6453 Pounds
PSBR20R 4 Inches 4 Inches - 0.21 Pounds
PSBR20G 3.5 Inches - 4 Inches 0.24 Pounds
PSBR20G-BHA 26.75 Inches - 4 Inches 0.61 Pounds

Product Specs

Cubic Capacity:
20 cu in
Insulated:
No
Number of Outlets:
1
Color Options:
Gray, Red
Mounting Feature:
Screw, Nail-On
Product Type:
Non-Metallic Ceiling Boxes, Non-Metallic Outlet Boxes
Product Group:
Electrical Boxes
Product Subgroup:
Junction Boxes
Product Diameter:
4 inches
Department:
Electrical

Centaur TAMCO-PSBR20 – Frequently Asked Questions

1) How many cubic inches is the Centaur PSBR20 round plastic box, and is that enough for a ceiling fixture with a couple of cable runs?
The Centaur round plastic box is a 20 cubic inch box with one device opening. Twenty cubic inches is on the larger side for a 4 inch round box, so it gives you working room for the fixture leads plus feed and switch-leg cable in a ceiling location. Box fill is counted per conductor by wire size, so size the cable count against the 20 cu in figure before you close it up.
2) Will a 4 inch round plastic box fit a standard round ceiling fixture canopy or fan-rated pan?
The Centaur box measures 4 inches in diameter, which is the standard round ceiling-box footprint round fixture canopies and round covers are made to. It's a non-metallic box for lighting fixtures, ceiling boxes and other round-device applications in new construction. Fan support is a separate question: this is a standard plastic outlet box, and a paddle fan needs a box specifically listed and braced for fan support.
3) Should I order the nail-on version or the bar hanger version of the Centaur round box?
Both mounting styles are offered on the Centaur 20 cu in round box. Nail-on mounts direct to the side of a stud or joist, which is what you want when the fixture lands where framing already is. The bar hanger version spans between joists so you can slide the box to the exact fixture centerline, which is how most ceiling lights get located in new construction. If the light is on a layout drawing rather than on a joist, take the bar hanger.
4) How much space does the bar hanger version of the Centaur round box need between joists?
The bar hanger assemblies are built for standard framing bays. The PSBR20-BHA measures 18.25 inches across at full extension and the grounded PSBR20G-BHA measures 26.75 inches, so the shorter bar suits 16 inch on-center framing and the longer one reaches across 24 inch on-center bays. Check which bay spacing you're working in before you pick, because the short bar will not span 24 inch centers.
5) Does the Centaur PSBR20 plastic box come with a ground screw or grounding clip?
It depends which version you order. The Centaur 20 cu in round box is sold with a grounding clip and also in a no-ground configuration. Plastic boxes don't bond to the equipment ground the way a metal box does, so if your fixture or device needs a ground termination point in the box, order the grounding clip version. The no-ground version is for runs where the ground is made up entirely on the fixture.
6) Can I use this Centaur plastic box in a remodel or old-work ceiling cut-in?
No. The Centaur round plastic box mounts by nail-on or screw to framing, or on a bar hanger spanning joists, which means you need access to the framing. That's a new-construction box, installed before the drywall goes up. For a cut-in on a finished ceiling you need an old-work box with retention ears that clamp to the drywall instead.
7) What is the red Centaur round box for versus the gray one?
The Centaur round box comes in gray and red. The red is a color-coded box, and on a jobsite that coding is how crews and inspectors tell one circuit family apart from another at a glance, typically emergency or fire-alarm circuits against normal power in gray. Electrically the red is the same 20 cubic inch, 4 inch round non-metallic box; the color is for identification, not a different rating.
8) Is the Centaur round plastic box insulated, and can it go in an insulated exterior ceiling or attic bay?
The Centaur round box is not an insulated box. It's a non-metallic, flame-retardant thermoplastic box that resists impact and corrosion, but it carries no insulating or air-seal construction. In a ceiling below a vented attic or on an insulated assembly where the drawings call for an airtight or vapor-barrier box, this one won't satisfy that detail.
9) How many Centaur PSBR20 boxes come in a case?
The Centaur 20 cu in round plastic box is packaged 75 per case. That's the buying unit for a rough-in, so figure your ceiling and switch box count per floor and order cases against it rather than singles.
10) Can I standardize all the ceiling light boxes in a multi-family build on one Centaur part?
Largely, yes. The Centaur round box is one 20 cubic inch, 4 inch round platform available nail-on or bar hanger, grounded or no-ground, gray or red, so a whole building's round-device rough-in can run off a single box family with only the mounting and grounding decision changing per opening. Practically, most crews carry the bar hanger for ceiling fixture locations and the nail-on for anything landing on framing.
11) How deep is the Centaur nail-on round box, and will it clear framing or a plate behind it?
The nail-on Centaur round boxes run about 4 inches across the face with the grounded PSBR20G listed at 3.5 inches on its other dimension, and the no-ground PSBR20R at 4 by 4 inches. On a nail-on, the box body sits against the face of the stud or joist with the front edge set out to finish flush with the drywall, so the framing member itself is what it needs to clear, not anything behind it.
How fast can I get the Centaur TAMCO-PSBR20 delivered?
Most orders ship the same day from our distribution partners, with quick delivery throughout the continental U.S. Need it urgently? Contact Us for expedited shipping options.
Can I return it if it doesn’t work for me?
Yes—ZenSupply offers a hassle-free return policy. If the product isn’t the right fit, reach out to our support team for a return authorization or setup a return by following our return instructions.
Does the Centaur TAMCO-PSBR20 come with a warranty?
Absolutely. The Centaur TAMCO-PSBR20 is backed by a manufacturer’s warranty. For full warranty terms, check the product documentation or Contact Us.
How do I get technical support or installation help for the Centaur TAMCO-PSBR20?
You can call, text, or email our expert support team for fast answers. We’re here to help with product selection, installation tips, and troubleshooting. Contact Us
Why buy the Centaur TAMCO-PSBR20 from ZenSupply?
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