Frequency selection isn’t about the utility. It’s about what’s around it. One of the most common mistakes I see in the field — techs defaulting to the same frequency every single time regardless of the environment. That’s how you end up marking the wrong line. Here’s how I think about it: 512 Hz is your long distance specialist. Minimal signal bleed, ideal for trace wire and telecom runs. Direct connect only — inductive clamp won’t work at this frequency. 8 kHz is your everyday workhorse. Solid range, works with both direct connect and inductive clamp, good balance between signal strength and bleed control. 33 kHz gives you a stronger signal and better clamp performance — but in a congested utility corridor, that stronger signal bleeds onto adjacent lines. Know what’s around you before you dial it in. The environment drives the frequency choice. Always.
The three frequencies:
512 Hz
Long distance | Trace wire | Minimal bleed
8 kHz
Everyday workhorse | Direct connect & clamp
33 kHz
Stronger signal | Watch bleed in dense corridors
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