NEMA 4 · PVC conduit

1-1/2" PVC conduit to a NEMA 4 box

For 1-1/2" PVC into a NEMA 4 / 4X enclosure: thread a Carlon E943H male terminal adapter into a Myers ST5 watertight hub. Punch the hole with a 1-1/2" conduit-size knockout punch, which cuts a 1.95 in (49.6 mm) hole.

Adapter · 1-1/2"E943HCarlon male terminal adapter
Hub · 1-1/2"ST5Myers zinc, NEMA 4/4X
Hole · 1-1/2"1.95 in49.6 mm · Greenlee K3P-1-1/2
Support · 1-1/2"5 ftmax spacing, NEC 352.30
This page is 1-1/2" only. Every part below is the 1-1/2" size. For a different conduit size, pick it in the size bar at the top. Don't mix sizes: an adapter only threads into the hub of the same size.

Option A for 1-1/2": watertight hub (keeps the NEMA 4 rating)

The hub mounts through the box wall with a captive O-ring on the outside face and its own locknut inside. The 1-1/2" male adapter threads into the hub, and the conduit is glued into the adapter. The O-ring is what keeps the NEMA 4 / 4X rating.

Cross-section of a hub connection through the bottom of an enclosure From the inside of the box down: the hub locknut, the box wall, the hub's O-ring, the hub body with female threads, the male terminal adapter threaded into the hub, and the PVC conduit glued into the adapter. INSIDE THE ENCLOSURE OUTSIDE 1-1/2" ONLY Hub locknut (inside) Box wall O-ring, outside face Myers ST5 / alt. hub Male thread into hub's female thread Carlon E943H male terminal adapter 1-1/2" PVC conduit, glued into socket Bottom entry shown: water drains away from the seal, not onto it.
Section through a bottom entry. Not to scale.

Order list: 1-1/2", Option A

SizeQtyPartMfr #Notes
1-1/2"11-1/2" PVC male terminal adapterCarlon E943HGlue the conduit into it. Male thread goes into the hub.
1-1/2"11-1/2" watertight hub, zincMyers ST5Crouse-Hinds (Eaton) Scru-Tite. Captive O-ring, insulated throat.
or, instead of the ST5:
1-1/2"11-1/2" watertight hub, aluminumMyers STA5Aluminum version of the ST5.
1-1/2"11-1/2" watertight hubAppleton HUB150ADie-cast aluminum, integral O-ring, insulated throat.
1-1/2"—PVC primer + solvent cementany listedRated for 1-1/2" conduit.

Option B for 1-1/2": sealing locknut (raintight only)

The adapter goes through the hole from outside. The sealing locknut goes on the outside face and a standard 1-1/2" locknut on the inside. Bridgeport lists these as raintight, with no watertight or NEMA 4 claim. If the box has to stay NEMA 4, use Option A.

SizeQtyPartMfr #Notes
1-1/2"11-1/2" PVC male terminal adapterCarlon E943HSame adapter as Option A.
1-1/2"11-1/2" sealing locknutBridgeport 145Steel with a PVC seal. "Provides raintight seal."
1-1/2"11-1/2" standard locknut (inside)any listedPlain, not sealing.

Hole size for 1-1/2"

Use the 1-1/2" conduit-size knockout punch (Greenlee K3P-1-1/2). It cuts a 1.95 in / 49.6 mm hole.

Knockout punches are labeled by the conduit size they're for, not by the hole they cut. A punch labeled with the hole diameter is a different tool.

Install steps for 1-1/2"

  1. Pick the entry. Use the bottom or a side. A top entry collects water against the seal.
  2. Punch the hole with the 1-1/2" conduit-size punch (1.95 in). Deburr both faces so the O-ring sits flat.
  3. Mount the Myers ST5 from outside with the O-ring against the outside face. Tighten the hub locknut from inside until the O-ring is evenly compressed. On fiberglass or polycarbonate boxes, stop at firm.
  4. Thread the Carlon E943H into the hub until it's snug. Don't crank on PVC threads. If you use thread sealant, pick one that's rated safe for PVC.
  5. Glue the 1-1/2" conduit into the adapter socket. Cut square, deburr, then prime and cement both surfaces. Push it fully home with a quarter turn and hold it for the cement's set time.
  6. Support it within 3 ft of the box and at no more than 5 ft spacing (NEC Table 352.30 for 1-1/2"; check your code edition).
  7. Check that the O-ring is evenly squeezed all the way around. If your equipment ground lands in this box, bond the hub's grounding screw.

Don't grab the neighboring size

The next size up and down use part numbers one step away. These are not for 1-1/2" conduit:

SizeAdapterMyers hubSealing locknut
1-1/4"One size smallerE943GST4144
2"One size largerE943JST6146

Also don't confuse Carlon E943 (male terminal adapter) with E942 (female adapter). At 2", for example, E942J is the female adapter.

Sources for 1-1/2"

← 1-1/4"2" →