Eaton 3/4 in. Conduit Hub for BR Panel: Sizing, CH vs Square D Compatibility

By ZenSupply Electrical Team · Reviewed by ZenSupply technical staff · Last updated June 18, 2026

What does an Eaton BR panel conduit hub actually do?

A conduit hub seals the entry point where conduit lands on a loadcenter. On a top-fed Eaton BR main breaker panel in a wet location, the hub does two jobs: it provides a threaded, raintight connection to rigid or IMC conduit, and it maintains the NEMA 3R rating of the enclosure.

Without a proper hub, a top knockout penetration on an outdoor panel violates the listing. Locknut-and-bushing fittings are not raintight on a top feed.

Eaton's BR and Cutler-Hammer CH platforms (the Cutler-Hammer commercial residential line) use proprietary hubs that bolt to the enclosure top via the integral hub provision. They're not generic — and they're not interchangeable across brands.

Which Eaton hub fits a BR load center?

Eaton publishes specific hub part numbers indexed to enclosure size and amperage. For BR-series loadcenters with rainproof top-feed provisions, the Eaton DS Rainproof Conduit Hub 200A NEMA 3R covers the larger main-breaker enclosures up to 200A service.

For smaller 70–125A BR and Cutler-Hammer CH MLO/MCB enclosures, Eaton supplies a dedicated 3/4 in. hub — see the Eaton Cutler-Hammer CH Conduit Hub 3/4 Inch NEMA 3R for 70-125A Loadcenters. For 150–225A frames, the Eaton Cutler-Hammer CH Conduit Hub 3/4 in NEMA 3R Up to 200A is the correct callout.

Verify the enclosure's catalog sheet before ordering. The same 3/4 in. trade size doesn't mean the same bolt pattern — Eaton groups hubs by enclosure family. If you're feeding a load center sub panel, the hub group still applies based on the can, not the function.

Are Eaton BR, CH, and Square D conduit hubs interchangeable?

No. Conduit hubs are listed to the specific enclosure they ship with under UL 50 / UL 50E and the manufacturer's own engineering. Cross-brand mounting is not approved.

Eaton BR and Cutler-Hammer CH hubs share some part numbers within the Eaton family (the Cutler-Hammer CH hub for 150–225A enclosures is documented for both MLO and MCB loadcenters). Square D QO and Homeline use a separate hub line with different bolt geometry and gasket profile. Siemens uses its own as well.

If you're swapping a panel and inheriting a hub, the safe assumption is: it doesn't fit. Order the hub that matches the enclosure brand and amperage. Same principle as breakers — you don't put a Square D QO into a BR can, and you don't put a Square D hub on a Cutler-Hammer CH loadcenter. For breaker selection, see our miniature circuit breakers inventory.

What knockout size does a 3/4 in. conduit hub require?

A 3/4 in. trade size hub seats into a 3/4 in. concentric knockout — nominally 1.109 in. (28.2 mm) ID. Eaton BR and Cutler-Hammer CH top-fed enclosures are punched with concentric KOs that step from 1/2 in. through 1 in. or larger, depending on the frame size.

For sizing the conduit run, match the hub to the conduit. A 3/4 in. hub takes 3/4 in. rigid, IMC, or threaded EMT (via a threaded EMT coupling). Shop conduit at EMT conduit or rigid fittings depending on the install.

If the panel ships with a larger concentric ring already open and you need to step down, that's a reducing washer conversation — see the final section. The wrong path is forcing a smaller hub into an oversized opening with no seal.

Need the right panel and hub for an outdoor service? Browse our main breaker panels and load centers — filter by NEMA 3R for rainproof enclosures that accept Eaton DS and Cutler-Hammer CH hubs out of the box.

Is the Eaton 3/4 in. BR conduit hub raintight or NEMA 3R rated?

Yes — Eaton's DS and Cutler-Hammer CH rainproof hubs are labeled for use with NEMA 3R loadcenters and are listed under UL 514B as raintight fittings. The hub maintains the wet-location integrity of the top feed when properly torqued onto the threaded entry and used with the supplied gasket.

This is the functional equivalent of a Myers-style hub: a malleable iron or steel body with an integral O-ring/gasket and a threaded hub that engages rigid or IMC conduit threads. The term "Myers hub" is generic — Eaton's branded hubs do the same job and are listed for the specific enclosure.

For the outdoor enclosure itself, see NEMA 3R enclosures.

How do you install a 3/4 in. hub on an Eaton BR top knockout?

Sequence:

1. Open the knockout cleanly. Use a knockout punch rather than a screwdriver. Ragged edges destroy the gasket seat.
2. Confirm the KO diameter matches 3/4 in. trade size (~1.109 in.). If you popped the wrong concentric ring, you're now reducing-washer territory.
3. Seat the hub body through the KO from outside with the gasket against the enclosure surface.
4. Install the locknut/retainer from inside per Eaton's instructions and torque to spec.
5. Thread the conduit into the hub. Rigid and IMC have NPT threads — engage at least five full threads.
6. Verify the gasket is compressed evenly. A cocked hub leaks.

Do you need a bonding bushing with an Eaton conduit hub?

Per NEC Article 250.92(B) and 250.97, service-entrance raceways and circuits over 250V to ground require bonding around concentric or eccentric knockouts — a standard locknut is not sufficient. The bonding path must be electrically continuous to the grounded service conductor.

Eaton's listed raintight hubs that mount in a clean, fully-removed knockout (not a concentric/eccentric ring) generally satisfy the bonding requirement through the hub-to-enclosure mechanical connection, but the AHJ has the call. When in doubt, add a bonding bushing or bonding jumper.

For the bonding hardware, see bonding jumpers and grounding screws. On feeder (non-service) panels at less than 250V to ground, a listed hub on a clean KO is typically acceptable.

How does the Eaton BR/Cutler-Hammer CH hub compare to other options?

Choose the Eaton DS / Cutler-Hammer CH rainproof hub when:

• You're feeding an Eaton BR or Cutler-Hammer CH NEMA 3R loadcenter top-down with rigid or IMC.
• Service entrance application requires UL 514B raintight listing matched to the enclosure.
• You need a factory-engineered gasket and bolt pattern — no field-improvised seals.
• The panel will be inspected against the original manufacturer's listing.

Choose a Square D HUB-style hub when:

• The enclosure is a Square D QO or Homeline NEMA 3R loadcenter.
• Brand-listed compatibility is required by the spec or AHJ.
• The original install used Square D throughout and you're matching warranty terms.

Choose a generic Myers-style raintight hub when:

• You're landing conduit on a generic junction box or pull box, not a listed loadcenter.
• The enclosure manufacturer permits third-party UL 514B raintight hubs.
• You need a standalone fitting for a meter socket or disconnect with a flat top.

Brand / Series	Listing	NEMA Rating	Best For	List Price Tier
Eaton DS Hub (200A)	UL 514B raintight	NEMA 3R	200A BR/Cutler-Hammer CH outdoor service entrance	Mid
Eaton Cutler-Hammer CH Hub 3/4 in (70–125A)	UL 514B raintight	NEMA 3R	70–125A BR/Cutler-Hammer CH MLO and MCB cans	Value
Eaton Cutler-Hammer CH Hub 3/4 in (150–225A)	UL 514B raintight	NEMA 3R	150–225A BR/Cutler-Hammer CH MLO and MCB cans	Mid
Square D HUB-series	UL 514B raintight	NEMA 3R	QO / Homeline outdoor loadcenters	Mid
Generic Myers-style raintight hub	UL 514B raintight	NEMA 3R (fitting)	Junction boxes, meter sockets, generic enclosures	Value

What are the common mistakes — reducing washers, cross-brand fitment, and service entrance use?

Reducing washers are not a substitute for the correct hub on a wet location. A reducing washer set adapts an oversized KO down to a smaller fitting in dry applications. On a NEMA 3R top feed, they don't maintain the raintight seal and they don't satisfy the listing.

If you opened a 1 in. concentric and need to land a 3/4 in. conduit, the right answer is usually a 3/4 in. raintight hub designed for the larger KO ring, or a properly listed reducing arrangement that the panel manufacturer approves. When the panel sheet doesn't list it, don't field-engineer it.

Cross-brand fitment is a recurring inspection failure. An Eaton Cutler-Hammer CH hub on a Square D QO panel is not listed. It may bolt up. It still fails inspection.

Service entrance use requires bonding. NEC 250.92(B) is non-negotiable on service raceways — verify your hub-to-enclosure path is bonded, or add the bushing.

For the full inventory of compatible Eaton enclosures and hubs, shop main breaker panels and load centers — match the hub to the can, not the other way around.