Power inlet box
Reliance Controls PB30 30 Amp Generator Inlet Box (L14-30)
A raintight metal box with a recessed L14-30 inlet that mounts on an outside wall — the place the generator cord plugs in, wired by an electrician to a transfer switch or an interlocked generator breaker.
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Best for
Interlock-kit and transfer-switch installs fed by a portable generator's L14-30 outlet
Specifications
| Rating | 30 A, 125/250 V |
|---|---|
| Inlet | NEMA L14-30 flanged inlet — takes the L14-30 connector end of a 4-wire generator cord |
| Enclosure | NEMA 3R raintight, metal (PB series), spring-loaded self-closing cover |
| Wiring | Copper only, #10 AWG minimum to #8 AWG maximum; four ½ in / ¾ in knockout combinations |
| Size | 4 × 6 × 3.75 in (W × H × D) |
| Listing | cULus listed |
| Warranty | 5-year limited |
Specifications as published by Reliance Controls. Confirm against the current spec sheet before buying — manufacturers revise models without renaming them.
What's good
- Power always arrives through the cord's shrouded female connector, so no exposed pin is ever live — the reason an inlet box beats any cord-to-panel shortcut
- Reliance rates it for any brand of transfer switch or generator-ready panel, not only its own
- The same inlet Reliance packs in its 31410CRK/310CRK kit, so the parts are known to work together
- Self-closing cover keeps rain, debris and insects out of the inlet between outages
What's not
- Electrician install, usually under a permit — Reliance's instructions require a qualified electrician working to code
- Only the connection point: Reliance states it must be used with a transfer switch when powering a building (or a listed interlock kit, where the inspector accepts one)
- No cord in the box — and the cord has to be long enough to keep the generator 20 ft from the house
- 30 A ceiling: a generator with a 50 A outlet needs a 50 A inlet such as Reliance's PB50
Our verdict
When an electrician fits an interlock kit, or a transfer switch without its own outdoor inlet, this is the box that goes on the outside wall. It is listed, raintight and the inlet Reliance ships in its own kit, so there is nothing to improvise — and owners of the 31410CRK already have one. Mount it where the generator can sit at least 20 feet out with the exhaust pointed away from the house, then buy a cord that reaches that spot rather than parking the generator where a short cord ends.
Compare with the alternatives
- Kidde COBD10 Carbon Monoxide Alarm — every level of the home and outside sleeping areas, before generator season
- Kidde 30CUD10-V Smoke + CO Alarm — hallways outside bedrooms, where a smoke alarm and a co alarm are both needed
- Southwire 12/3 SJTW 50 ft Outdoor Extension Cord (2588SW0002) — running a fridge, freezer or space heater from a portable generator at a safe distance
- Reliance Controls Pro/Tran 10-Circuit Transfer Switch Kit (31410CRK / 310CRK) — portable generators up to 7,500 running watts with an l14-30 outlet
- WEN PC3025 30-Amp Generator Power Cord, 25 ft (L14-30P to L14-30R) — connecting an l14-30 generator to a house inlet from 20 feet or more away
- STA-BIL Storage Fuel Stabilizer, 16 oz (22207) — gasoline generators and stored fuel cans that sit for months between outages
- Southwire Surge Guard Generator Neutral-Ground Bonding Plug (44400) — a floating-neutral generator run on cords, when an rv surge protector reports open ground or an ev charger refuses to start