Increase Electrical Safety with Design Best Practices

Apply Guidant Power’s arc flash engineering knowledge to help mitigate electrical risk before installation.

Arc Flash Mitigation Through Design

Our involvement in the design process typically includes several key recommendations for reducing arc flash hazards:

Select the Right Overcurrent Protective Devices (OCPDs) Choose breakers or fuses that help reduce available incident energy. To determine if a selected OCPD will reduce arc flash energy, a full arc flash evaluation is required—not just for the new equipment, but also for everything upstream to ensure proper fault current is used and that coordination is achieved. Optimize the Location of OCPDs

If large arc flash hazards are present, install the main breakers in a separate enclosure to isolate high-hazard equipment from other areas a worker might interact with. For main switchgear, this might mean moving the breaker into another room or outdoors, near the transformer.

Add a Secondary Main Breaker at the Switchgear

Placing an additional main breaker at the switchgear allows for safer isolation at a lower arc flash energy level. While the outdoor breaker moves the hazard outside, this secondary breaker enables safer operation during non-normal conditions (as defined by NFPA 70E).

Install Local Disconnects Separately

Locate local disconnects in a separate enclosure at floor-level equipment. For example, mount a fused disconnect or main breaker in a small enclosure on the side of the equipment’s enclosure. This supports better lockout/tagout (LOTO) and hazard isolation, though it may increase upfront cost.

Protect Transformer Secondaries

Install an OCPD on the secondary side of dry-type transformers upstream of the connected equipment. Transformers over 30kVA often present arc flash hazards (≥4 cal/cm²) on the secondary. Frequent interaction with equipment connected to the secondary side of a transformer of this size should have arc flash risk mitigated through design. This OCPD is not meant for routine interaction but strictly for arc flash mitigation, with LOTO performed on the transformer’s primary side.

Use Breakers with Electronic Trip Units

These breakers can significantly reduce arc flash energy when thermal breakers or fuses fall short. Reduction capability must always be confirmed through engineering calculations.

Model Arc Flash Before Purchasing Equipment

Perform arc flash modeling in advance to determine if reduction is needed. Hazards are often only revealed through calculations. More information about what causes different arc flash sizes can be found here. At Guidant Power, we can model and verify if reduction is necessary.

Many customers consult us with part numbers before making purchases. We can also calculate available fault current throughout the system to avoid overpaying for unnecessarily high duty-rated gear.

Design Out the Hazard When Possible

There are many arc flash reduction strategies—flash sensors, arc-rated gear, etc.—but if arc flash risk can be designed out from the start, there's no need to rely on sensors or trip mechanisms to respond to a fault.

Shock Hazard Mitigation by Design

Use Covers and Finger-Safe Components

Design equipment with covers and IP20 (or better) finger-safe terminals. See Rozel’s post for guidance on what qualifies as “exposed.”

Relocate Overload Resets

If overloads are likely to occur, place reset buttons away from shock hazards. OSHA allows resetting under certain conditions, but design should ensure safety during this process.

Use Voltage-Absence Verification Tools

Components like Panduit’s VeriSafe or Grace Technologies’ PESDs offer safer ways to verify voltage absence.

Install IR Ports or Remote Monitoring

These tools reduce the need to open panels and expose workers to potential shock hazards.

Maintain Equipment Integrity

After service, always replace all original fasteners. For example, if a cover was designed with six screws, ensure all six are reinstalled to maintain the intended safety rating.

Policy Support and Cost Considerations

Safety Policy Review or Creation

We assist with writing full safety policies or developing task-specific SOPs tailored to your facility.

Potential Cost Savings from a Guidant Power Review

We’ve helped clients avoid unnecessary purchases —such as maintenance mode add-ons or specialty fuses—by verifying what’s actually effective through engineering analysis.

While there may be upfront costs for a Guidant Power review, the savings in the event of an arc flash incident can be substantial—often many times more than the cost of a replacement breaker or trip unit.