A studio shot of the Klein Tools ET310 kit showing the handheld digital circuit breaker receiver and the matching GFCI outlet transmitter. Both components feature a rugged orange and black plastic housing.
Product infographic for the ET310 highlighting key features with callout lines: visual and audible indicators on the receiver tip, a button to test GFCI devices on the transmitter, and a docking port where the transmitter stores inside the base of the receiver.
Close-up diagram of the ET310 transmitter showing the GFCI test button, a list of wiring condition codes, and three light indicators. A corresponding table explains various light combinations for conditions such as Open Ground, Open Hot, and Correct Wiring.
Side-by-side view of the ET310 digital circuit breaker receiver standing vertically next to the compact GFCI outlet transmitter, shown against a plain white background.
An angled view of the Klein Tools ET310 with the transmitter securely docked into the bottom of the receiver, demonstrating how the two pieces fit together for unified storage.
The ET310 receiver and transmitter shown apart, angled to illustrate how the three-pin plug of the transmitter aligns with the storage outlet on the bottom of the handheld receiver.
A horizontal view of the ET310 system with the transmitter positioned just outside the receiver's storage dock, highlighting the L-shaped ergonomic design of the receiver handle.
A perspective shot of the ET310 kit components laid out on a white surface, showing the receiver's power/reset button and the transmitter's North American style grounded plug.
A studio shot of the ET310 transmitter docked into the receiver, showing the full combined length of the tool and the clear labeling for the GFCI tester indicators.
Action shot of a technician using the ET310 receiver to scan a gray electrical panel. The tip of the receiver is glowing green, indicating it has successfully located the correct circuit breaker.
Close-up action shot of a person’s hand plugging the orange ET310 transmitter into a standard white North American grounded electrical outlet to test the circuit wiring.
Digital Circuit Breaker Finder with GFCI Outlet Tester (ET310) promotional video
A studio shot of the Klein Tools ET310 kit showing the handheld digital circuit breaker receiver and the matching GFCI outlet transmitter. Both components feature a rugged orange and black plastic housing.
Product infographic for the ET310 highlighting key features with callout lines: visual and audible indicators on the receiver tip, a button to test GFCI devices on the transmitter, and a docking port where the transmitter stores inside the base of the receiver.
Close-up diagram of the ET310 transmitter showing the GFCI test button, a list of wiring condition codes, and three light indicators. A corresponding table explains various light combinations for conditions such as Open Ground, Open Hot, and Correct Wiring.
Side-by-side view of the ET310 digital circuit breaker receiver standing vertically next to the compact GFCI outlet transmitter, shown against a plain white background.
An angled view of the Klein Tools ET310 with the transmitter securely docked into the bottom of the receiver, demonstrating how the two pieces fit together for unified storage.
The ET310 receiver and transmitter shown apart, angled to illustrate how the three-pin plug of the transmitter aligns with the storage outlet on the bottom of the handheld receiver.
A horizontal view of the ET310 system with the transmitter positioned just outside the receiver's storage dock, highlighting the L-shaped ergonomic design of the receiver handle.
A perspective shot of the ET310 kit components laid out on a white surface, showing the receiver's power/reset button and the transmitter's North American style grounded plug.
A studio shot of the ET310 transmitter docked into the receiver, showing the full combined length of the tool and the clear labeling for the GFCI tester indicators.
Action shot of a technician using the ET310 receiver to scan a gray electrical panel. The tip of the receiver is glowing green, indicating it has successfully located the correct circuit breaker.
Close-up action shot of a person’s hand plugging the orange ET310 transmitter into a standard white North American grounded electrical outlet to test the circuit wiring.
Digital Circuit Breaker Finder with GFCI Outlet Tester (ET310) promotional video
KLEIN TOOLS

Klein Tools Circuit Breaker Finder ET310 GFCI Outlet Tester Kit (90-120V AC CAT II 120V Panel Location Transmitter Docking Receiver)

Only 3 left
SKU: ET310
$49.97 USD

Description

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Contractor-Grade Digital Circuit Identifier for Rapid Panel Mapping and Grounded GFCI Outlet Diagnostic Testing

The Klein Tools ET310 Digital Circuit Breaker Finder and GFCI Outlet Tester Kit delivers professional-grade diagnostic speed when mapping building branch circuits, testing receptacle safety relays, and auditing commercial panels. Operating across a standard 90-120V AC electrical range, this two-piece system utilizes a transmitter to broadcast digital tracking signatures into active branch lines while the handheld receiver tracks the signal down to a specific electrical fuse position. The precision system features visual and audible alert arrays that guide a single technician to the precise breaker profile, solving the time-wasting panel verification problems common during residential remodeling layouts. Certified with a strict CAT II 120V safety classification and built to withstand a 6.6-foot impact drop, this trade-focused testing assembly integrates a modular docking chassis for convenient tool bag storage.

Best Used For:

  • Single-User Circuit Mapping: Locating the exact controlling breaker inside crowded service panels before beginning downstream outlet replacements or lighting fixture wiring.
  • GFCI Receptacle Auditing: Inspecting the wiring status of North American grounded sockets and executing controlled trip sequences to ensure ground-fault safety functions.
  • Commercial Building Remodels: Verifying wiring conditions, trace paths, and open ground faults across multi-circuit branch lines during tenant build-outs.

Key Performance & Safety Features

  • Microprocessor-Driven Alignment: Receiver processor auto-calibrates sensitivity thresholds to avoid cross-talk readings from adjacent panel lines.
  • Integrated GFCI Diagnostic Circuit: Built-in tester detects common wiring errors including open ground, open neutral, and reversed polarity states.
  • Simultaneous Signal Arrays: Handheld tracking wand outputs high-frequency audible tones and clear LED flashes when passing over targeted fuses.
  • Modular Docking Chassis: Heavy-duty transmitter locks flush into the receiver housing cavity, protecting vulnerable socket plugs from bending during transit.
  • Automatic Battery Shielding: Internal battery conservation timers auto-terminate receiver system power after three minutes of jobsite inactivity.

What's Included

  • (1) Digital Circuit Breaker Finder Receiver
  • (1) Integrated GFCI Receptacle Transmitter
  • (1) Heavy-Duty 9V Alkaline Battery (For Receiver Unit)
  • (1) Step-by-Step User Manual

Technical Specifications

Specification Value
Brand Klein Tools
Model Number ET310
Tester Class Type Electronic Breaker Locator & Receptacle Auditor
Voltage Range Capacity 90 - 120V AC
Safety Rating Category CAT II 120V
Drop Protection Spec 6.6 Feet (2 Meters)
Overall Body Length 10.96 Inches
Overall Body Height 2.16 Inches
Overall Body Width 1.39 Inches
Net Tool Weight 7.2 oz
Power Cell Requirement 1 x 9V Block Battery (Included)

Pro-Tip: When tracking circuits in panels with closely situated breakers, sweep the receiver wand completely down the full sequence of switches once before executing the final selection. This initial calibration pass allows the microchip to index comparative signal strengths, ensuring absolute accuracy on the second tracing cycle.