PVC conduit to a NEMA 4 box: every size, 1/2" to 6"
To land PVC in a NEMA 4 or 4X enclosure and keep the rating, thread a Carlon E943-series male terminal adapter into a Myers watertight hub of the same size. Pick your size below. Each size has its own page with only that size's parts.
Pick your conduit size
Two common mix-ups:
- Carlon E942 is the female adapter. The male terminal adapter that goes into a hub is E943.
- Knockout punches are labeled by conduit size. For 2" conduit, use the 2" conduit punch, which cuts a 2.42" hole. Don't buy a punch labeled 2-1/2".
All sizes at a glance
One row per size, colored to match the size pages. Click a size to see its full parts list. A dash means no listing was found for that size.
| Size | Carlon adapter | Myers hub (zinc) | Myers hub (alum.) | Appleton hub | Bridgeport sealing locknut | Knockout hole | Max support |
|---|---|---|---|---|---|---|---|
| 1/2" | E943D | ST1 | STA1 | HUB50A | 141 | 0.89 in 22.5 mm | 3 ft |
| 3/4" | E943E | ST2 | STA2 | HUB75A | 142 | 1.12 in 28.3 mm | 3 ft |
| 1" | E943F | ST3 | STA3 | HUB100A | 143 | 1.36 in 34.6 mm | 3 ft |
| 1-1/4" | E943G | ST4 | STA4 | HUB125A* | 144 | 1.70 in 43.2 mm | 5 ft |
| 1-1/2" | E943H | ST5 | STA5 | HUB150A | 145 | 1.95 in 49.6 mm | 5 ft |
| 2" | E943J | ST6 | STA6 | HUB200A | 146 | 2.42 in 61.5 mm | 5 ft |
| 2-1/2" | E943K | ST7 | — | HUB250A | 147 | 2.88–2.91 in 73–74 mm | 6 ft |
| 3" | E943L | ST8 | STA8 | HUB300A | 148 | 3.54 in 89.9 mm | 6 ft |
| 3-1/2" | E943M | ST9 | — | HUB350A | 149 | 4.04 in 102.7 mm | 7 ft |
| 4" | E943N | ST10 | STA10 | HUB400A | 150 | 4.54 in 115.4 mm | 7 ft |
| 5" | E943P | ST11 | — | — | — | 5-5/8 (5.625) in 143 mm | 7 ft |
| 6" | E943R | ST12 | — | — | — | 6-3/4 (6.75) in 171 mm | 8 ft |
* HUB125A: listings disagree on whether it's aluminum or malleable iron, so confirm with your supplier. Support spacing is from NEC Table 352.30; check your code edition. Sealing locknuts are raintight, not NEMA 4.
How the connection works
Option A (keeps NEMA 4): the hub mounts through the box wall with a captive O-ring outside and a locknut inside. The male adapter threads into the hub, and the conduit is glued into the adapter.
Option B (raintight only): the male adapter goes through the hole, with a Bridgeport sealing locknut outside and a plain locknut inside. Cheaper, but Bridgeport lists it as raintight with no NEMA 4 claim.
Field tips (all sizes)
- Same size, top to bottom: the conduit, adapter, hub and punch must all be the same trade size.
- Schedule 40 vs 80: both have the same outside diameter, so the same adapter socket takes either.
- Expansion: PVC grows about 4 in per 100 ft for every 100 °F of temperature change. On long runs in the sun, add an expansion fitting so the movement doesn't pull on the hub.
- Condensation: a sealed box still collects condensation. A listed drain/breather fitting at the low point handles it.
- Fiberglass and polycarbonate boxes: the hubs here are metal. No 2" nonmetallic NEMA 4X hub was found. Use the metal hub, buy a box with a molded-in hub, or ask your supplier to search the Carlon and Arlington catalogs.
- Dry-fit first: thread one adapter into one hub before ordering a whole job's worth.
Questions
What connects PVC conduit to a NEMA 4 box?
A Carlon E943-series male terminal adapter threaded into a NEMA 4/4X watertight hub of the same size (Myers ST-series zinc, Myers STA-series aluminum, or Appleton HUB_A).
How are the Carlon part numbers sized?
The last letter is the size: D 1/2", E 3/4", F 1", G 1-1/4", H 1-1/2", J 2", K 2-1/2", L 3", M 3-1/2", N 4", P 5", R 6".
How are the Myers hub numbers sized?
They count up through the trade sizes: ST1 is 1/2", ST6 is 2", ST10 is 4", ST12 is 6". The STA prefix is the aluminum version.
Is a sealing locknut enough for NEMA 4?
No. Bridgeport's sealing locknuts are listed raintight (UL 514B) with no watertight or NEMA 4 claim. Use a hub listed NEMA 4/4X.
Are there sealing locknuts for 5" and 6"?
No Bridgeport listing was found above 4" (part 150). Use the hub.