Power lines. Signals. When the lift is critical.
Working notes we use before a study starts. Written in JMR language. This page is not ASME B30.5, not BS 7121, and not your site procedure. Buy and apply the current standard that governs that crane on that ground.
Keep the crane out of the zone.
Preferred condition: the line is isolated, grounded and confirmed by the utility on site. If the line stays live, treat clearance as a hard hold-point — not a guess from the cab.
Minimum clearance while the crane is operating, from OSHA 29 CFR 1926.1408 Table A. Metres in brackets are conversions of the published feet values.
| Nominal voltage (kV, AC) | Clearance while operating |
|---|---|
| Up to 50 | 10 ft (3.1 m) |
| Over 50 to 200 | 15 ft (4.6 m) |
| Over 200 to 350 | 20 ft (6.1 m) |
| Over 350 to 500 | 25 ft (7.6 m) |
| Over 500 to 750 | 35 ft (10.7 m) |
| Over 750 to 1,000 | 45 ft (13.7 m) |
| Over 1,000 | Set with the utility or a qualified electrical engineer |
Travel / transit with no load and boom lowered is a different table (OSHA 1926.1408 Table T). Distances shrink, but only in that configuration. Do not use travel figures while hoisting.
| Nominal voltage (kV, AC) | Clearance in travel, boom down, no load |
|---|---|
| Up to 0.75 | 4 ft (1.2 m) |
| Over 0.75 to 50 | 6 ft (1.8 m) |
| Over 50 to 345 | 10 ft (3.1 m) |
| Over 345 to 750 | 16 ft (4.9 m) |
| Over 750 to 1,000 | 20 ft (6.1 m) |
| Over 1,000 | Set with the utility |
Source: OSHA 29 CFR 1926.1408, public US regulation. ASME B30.5 has its own clauses on the same subject — we do not reproduce them here. Always take the stricter of the applicable documents.
One language. Agreed before the hook moves.
Radio can be primary. Hand signals stay as backup. The banksman and the operator brief the same set. If comms drop, the lift stops — there is no “guess the last order”.
- Hoist Forearm up, finger pointing up, small horizontal circle.
- Lower Arm down, finger pointing down, small horizontal circle.
- Use main hoist Tap the fist on the head, then the motion signal.
- Use whip / aux Tap the elbow, then the motion signal.
- Raise boom Arm out, thumb up.
- Lower boom Arm out, thumb down.
- Move slowly One hand gives the motion; the other stays still in front of it.
- Boom up, load down Arm out, thumb up, fingers flexing.
- Boom down, load up Arm out, thumb down, fingers flexing.
- Swing Arm out, point the way the boom must travel.
- Stop Arm out, palm down, sweep back and forth.
- Emergency stop Both arms out, palms down, both sweep.
- Travel Push in the travel direction, hand open.
- Dog everything Hands clasped in front of the body — hold the last command.
- Extend boom Both fists in front, thumbs pointing out.
- Retract boom Both fists in front, thumbs pointing in.
These are common industry signals described in JMR words. They are not official ASME plates. Train the crew on the set that the site procedure names.
When we will not treat it as routine.
“Critical” is a company and client word as much as a code word. ASME B30.5 Appendix A is non-mandatory. If the client, the duty holder or BS 7121 is stricter, that rule wins. On JMR studies we treat a lift as critical — written plan, named AP, pre-lift meeting — when any of these is true:
- Utilisation at the working radius is at or above the cap we set for that job (we use 75% unless the client sets lower).
- Two or more cranes share the same load, including a tailing crane.
- People are in a basket or on a suspended platform.
- The load is unique, long-lead or not replaceable if dropped.
- Weight or structural integrity is not proven (demolition, unknown CoG, no weigh).
- The path is inside a boom-length of an energized line, over live plant, a public road, a building with people, or a process that cannot be hit.
- Clearance is tight, the landing is blind, or control of the load at height is poor.
- The rigging is purpose-designed (frame, beam, unusual hitch) rather than catalogue slings on known points.
A critical plan, in our work, always names the total lifted weight (load + block + below-hook gear), the crane duty and radius, the rigging geometry, the path and the ground or vessel support. It is signed. The crew meets on that revision before the first hoist. If the plan changes on the day, the meeting runs again — we do not “carry on and write it later”.
Field notes are not the code.
Is this ASME B30.5?
No. We do not republish ASME text, tables or figures. Buy B30.5 from ASME if that volume applies to the crane. This page is a JMR briefing aid.
Why OSHA numbers then?
Those operating and travel distances are published in US federal regulation and are public. They are a useful floor. They are not automatically legal on an Angolan platform, a UK site under LOLER, or a Gulf project under company lifting procedure.
Will JMR sign a lift because I ticked this page?
No. A signed plan is a paid study for that load, that crane and that site.
Near a line, or over 75%. Send the brief.
Voltage, radius, chart and a sketch of the path is enough for a free preliminary view. If it is critical, we will say so before we quote.
contact@jmrlifting.com · Field notes v1.0 · August 2026