Using Arc-Fault Circuit Interrupter (AFCI) Breakers

An Arc-Fault Circuit Interrupter (AFCI) is a safety device designed to help protect against fires resulting from unsafe wiring conditions. The AFCI monitors current flow.  Once an unwanted arcing condition is detected, the control circuitry de-energizes (trips) the circuit.

The 2002 edition of the National Electrical Code (section 210-12) requires all branch circuits that supply 125-volt, single-phase, 15- and 20-ampere outlets installed in dwelling unit bedrooms to be protected by an arc-fault circuit interrupter listed to provide protection of the entire branch circuit. This requirement became effective January, 2002 for all new installations.

Lutron uses phase-control dimming technology in its products.

Phase-control dimmers may cause nuisance tripping when used with Arc-Fault Circuit Interrupters (AFCIs). This is because Arc-Fault Circuit Interrupters can interpret a dimmer turning on as an arc-fault condition. This nuisance tripping is dependent on the load wattage and the number of high wattage lamps on each Arc-Fault Circuit Interrupter. The use of high wattage lamps or large wattage loads will increase the chance of nuisance tripping when a dimmer turns on. This is only an issue when a dimmed circuit turns on and is not encountered during dimming or fades.

To avoid nuisance tripping of Arc-Fault Circuit Interrupters when connected to Lutron dimming equipment, the following guideline should be followed:

• Do not place more than 1000W of dimming load on each Arc-Fault Circuit Interrupter.

Note: This is limited to dimming loads only, all non-dim loads can operate at their maximum wattage.

1. RPM Panels

Dimming modules (4Us & 4Es) accept one dedicated feed from the distribution panel. The outputs on modules fed by AFCIs must be chosen manually.  When placing AFCI controlled loads on modules, observe the following rules:

• To minimize the required number of AFCI breakers, place all AFCI controlled loads together. 

• Do not place more than 1000W of dimming load on each Arc-Fault Circuit Interrupter breaker.

The HWI Panel Wizard may be used first to optimize the job without AFCIs as follows:

• Launch the panel wizard.
• When placing RPM loads in groups, place all AFCI controlled loads in a separate temporary group ("AFCI Group").
• After the Panel Wizard is completed, delete the temporary group ("AFCI Group").
• All AFCI loads will now show up as unassigned.
• Enter equipment (modules, enclosures, etc.) in manually to handle the AFCI controlled loads. Assign AFCI controlled loads to RPMs.  Do not place more than 1000W of dimming load on each Arc-Fault Circuit Interrupter. Leave module outputs empty or add power boosters to stay below 1000W of dimming. Each power booster added must be placed on a separate AFCI.

2. GRAFIK Eye Main Units

Do not place more than 1000W of dimming load on GRAFIK Eye Main Units fed by AFCIs. If you need to exceed 1000 W of dimming on a GRAFIK Eye, use 1 or more power boosters. Each power booster must be placed on a separate AFCI.

Yes. The panels may be modified to accommodate the installation of AFCI breakers. For questions on retrofitting AFCI breakers into the HWBP-8D and HWBP-2S panels, you may contact Jon Keagy at (610) 282-7446.

Last revised 9-10-02

© 2002 Lutron Electronics Co., Inc.  All rights reserved.