Electric signs disconnecting means

Yes. Each sign and outline lighting system, or the feeder or branch circuit supplying it, must be controlled by an externally operable switch or circuit breaker that opens all ungrounded conductors, with two limited exceptions. The standard requires this externally operable disconnect in 1910.306(a)(1)(i), and it explicitly exempts (1) an exit directional sign located within a building and (2) cord‑connected signs that use an attachment plug.

The disconnect must be at least 1.52 meters (5 feet) away from the inside walls of the fountain. That distance requirement is stated in 1910.306(a)(1)(ii) to reduce the risk of electric shock from moisture and water exposure.

The disconnecting means must be within sight of the sign or outline lighting it controls; if it is not within line of sight of any section that may be energized, it must be capable of being locked in the open position. This is required by 1910.306(a)(2)(i). Locking the disconnect open prevents accidental reenergization when workers cannot see the energized section.

You may locate the disconnect within sight of the external controller or in the same enclosure with the controller, but it must disconnect both the sign (or outline lighting) and the controller from all ungrounded supply conductors, be designed so no pole can be operated independently, and be capable of being locked open. These requirements are in 1910.306(a)(2)(ii). The intent is to ensure the entire system is deenergized and cannot be partially reconnected.

Those doors or covers must either have interlock switches that disconnect the primary circuit or be fastened so that opening them requires more than ordinary tools. This requirement appears in 1910.306(a)(2)(iii) and prevents unqualified persons from inadvertently contacting live high-voltage parts.

A disconnecting means (such as a motor‑circuit switch, circuit breaker, or molded case switch) must be provided and it must open all ungrounded conductors, be readily accessible and operable from the ground or floor level, be arrangable to be locked in the open position, and be placed within view of the runway contact conductors. These requirements are set out in 1910.306(b)(1) and the related crane/hoist paragraphs at 1910.306(b)(2)(i). They ensure safe deenergization for inspection and maintenance.

The disconnecting means may be omitted only if all three conditions are met: (A) the unit is controlled from the ground or floor level, (B) the unit is within view of the power supply disconnecting means, and (C) no fixed work platform has been provided for servicing the unit. These three specific conditions are listed in 1910.306(b)(2)(iv)(A)–(C). If any condition is not met, a disconnecting means is required.

Yes. A limit switch or other device must be provided to prevent the load block from passing the safe upper limit of travel of any hoisting mechanism. This safety feature is required by 1910.306(b)(3) to prevent over‑travel and potential mechanical failure or collision.

The minimum working space in the direction of access to live parts that may require examination, adjustment, servicing, or maintenance while alive is 762 mm (2.5 ft), and cabinet doors for enclosed controls must either open at least 90 degrees or be removable. These requirements are in 1910.306(b)(4) to provide safe access for qualified personnel.

Each elevator, dumbwaiter, escalator, moving walk, wheelchair lift, and stairway chair lift must have a single means for disconnecting all ungrounded main power supply conductors for that unit. That single‑means requirement appears in 1910.306(c)(1) and ensures a straightforward method to deenergize the unit for maintenance or emergency shutdown.

The disconnecting means must be an enclosed externally operable fused motor circuit switch or circuit breaker that is capable of being locked in the open position and must be a listed device. This specification is contained in 1910.306(c)(3) to ensure reliable, serviceable, and lockable equipment.

The disconnecting means must be readily accessible to qualified persons and, on elevators without generator field control, must be located within sight of the motor controller; if driving machines or controllers are not within sight of the disconnect, a manually operated switch must be installed adjacent to the equipment to prevent starting. These location and control rules are in 1910.306(c)(5)(i) and 1910.306(c)(6). They prevent unexpected startup while maintenance is being performed.

Yes. When there is more than one driving machine in a machine room, each disconnecting means must be numbered to correspond to the driving machine it controls, and the disconnect must have a sign identifying the location of the supply‑side overcurrent protective device. These identification requirements are in 1910.306(c)(6)(i)–(ii). Clear labeling helps safe isolation and troubleshooting.

A warning sign must be mounted on or next to the disconnecting means where multiple disconnecting means are used and parts of controllers remain energized from another source, and it must read exactly “WARNING - PARTS OF THE CONTROLLER ARE NOT DEENERGIZED BY THIS SWITCH.” This requirement and the identical wording for interconnections in multicar controllers are in 1910.306(c)(8)–(9). The sign warns technicians that opening that switch will not deenergize all controller parts.

Yes, motor controllers may be located outside the normally required spaces provided they are in enclosures with doors or removable panels capable of being locked closed and the disconnecting means is adjacent to or integral with the motor controller. This allowance and conditions are in 1910.306(c)(10). It lets controllers be placed in alternate locations only when secure and accompanied by an accessible disconnect.

Arc welders that do not have an integral disconnect must have a supply‑circuit disconnect (switch or circuit breaker) provided, sized at least to accommodate overcurrent protection; resistance welders and their control equipment must have a switch or circuit breaker sized not less than the supply conductor ampacity. These specific welder disconnect rules are in 1910.306(d)(1)–(2). The supply circuit switch for a circuit serving just one welder may serve as that welder’s disconnect.

You must provide a means to disconnect power to all electronic equipment in an information technology equipment room and a similar means to disconnect dedicated HVAC systems serving the room; the controls must be grouped, identified, and readily accessible at the principal exit doors. A single means to control both systems is permitted. These requirements are in 1910.306(e)(1) and the grouping/control guidance follows in 1910.306(e)(2)–(3). Integrated electrical systems covered by 1910.308(g) are excepted from the paragraph (e)(1) disconnect requirement.

A disconnecting means must be provided in the supply circuit and be operable from a location readily accessible from the X‑ray control; for equipment on a 120‑volt branch circuit of 30 amperes or less, a properly rated grounding‑type attachment plug and receptacle may serve as the disconnect. These requirements are in 1910.306(f)(1)(i). If multiple pieces share the same high‑voltage circuit, each piece or group must have a high‑voltage switch or equivalent disconnect constructed or located to prevent contact with live parts, as in 1910.306(f)(1)(ii).

Radiographic and fluoroscopic‑type equipment must be effectively enclosed or provided with interlocks that automatically deenergize the equipment to prevent ready access to live current‑carrying parts; diffraction and irradiation equipment must have a pilot light, readable meter deflection, or equivalent to indicate when energized unless effectively enclosed or interlocked. These control and indicator requirements are in 1910.306(f)(2)(i)–(ii). They ensure visible or automatic protection against unexpected exposure to live parts.

The converting apparatus (including the dc line) and high‑frequency electric circuits must be completely contained within enclosures of noncombustible material, all panel controls must be dead‑front, and doors or detachable panels shall be used for internal access. These guarding and enclosure rules are in 1910.306(g)(1)(i)–(iii). They reduce fire and electric shock hazards from high‑frequency and high‑voltage circuits.

You must provide either door locks or interlocks for doors that give access to voltages from 500 to 1,000 volts AC or DC.

• The plain requirement appears in 1910.306(g)(1), which states that for access to voltages from 500 to 1000 volts, either door locks shall be provided or interlocks shall be installed.
• Make sure the chosen method actually prevents accidental contact with energized parts when doors are opened.

For equipment over 1,000 volts AC or DC you must either provide mechanical lockouts that include a disconnecting means to prevent access until the circuit is deenergized, or provide both door interlocks and mechanical door locks.

• That requirement is stated in 1910.306(g)(1).
• Also, detachable panels not normally used for access should be fastened so they are difficult to remove (for example, require tools).

Warning labels “DANGER - HIGH VOLTAGE - KEEP OUT” must be attached and clearly visible where people might contact energized parts when doors are opened or panels removed from compartments containing over 250 volts AC or DC.

• See the specific text in 1910.306(g)(1)(iv).
• Make sure labels are placed so they are plainly visible during the normal opening or removal operations.

Induction heating coils must be protected by insulation or refractory materials, or both.

• This protection requirement is in 1910.306(g)(1)(v)(B).
• For other applicators (not the coils), 1910.306(g)(1)(v)(A) requires protective cages or adequate shielding.

All hinged access doors, sliding panels, or similar access to the applicator must have interlock switches, unless the applicator is an induction heating coil at DC ground potential or operating at less than 150 volts AC; interlocks must be wired to remove all power to the applicator when any access is open.

• See 1910.306(g)(1)(v)(C) for the scope of the interlock requirement and 1910.306(g)(1)(v)(D) for the requirement that interlocks remove all power when any one access door or panel is open.
• Verify wiring so a single open panel actually de-energizes the applicator.

Each heating equipment must have a readily accessible disconnecting means whose ampere rating is not less than the equipment's nameplate current rating; the supply circuit disconnecting means can serve as the equipment disconnect if it supplies only that piece of equipment.

• This is stated at 1910.306(g)(1)(vi).
• Ensure the disconnect is easy to reach, sized appropriately, and if shared, only used when the circuit supplies a single piece of equipment.

When remote controls are used for applying power, you must provide a selector switch interlocked to allow power from only one control point at a time.

• The selector switch/interlock requirement is in 1910.306(g)(2)(i).
• This prevents simultaneous conflicting commands from multiple control stations.

Foot-operated switches must have a shield over the contact button to prevent accidental closing of the switch.

• That requirement is in 1910.306(g)(2)(ii).
• The shield helps prevent unintended activation from debris or incidental contact.

Installations covered by 1910.306(h) must comply with all applicable provisions of the subpart except that: overcurrent protection of cell DC process power circuits need not meet 1910.304(f); equipment within the cell line working zone need not meet 1910.304(g); and electrolytic cells, cell line conductors, attachments, and auxiliary wiring within the working zone need not comply with 1910.303 or 1910.304(b) and (c).

• See the detailed exceptions in 1910.306(h)(1).
• These are narrowly framed exceptions that apply only to the specific electrolytic cell processes listed in the standard's scope.

If more than one DC cell line power supply serves the same cell line, a disconnecting means must be provided on the cell line circuit side of each power supply to disconnect that supply from the cell line.

• The requirement is stated in 1910.306(h)(2).
• Disconnects can be devices like switches, breakers, or removable links as allowed by the standard.

Yes; removable links or removable conductors may be used as the disconnecting means.

• This allowance is explicitly stated in 1910.306(h)(3).
• When using removable links, ensure procedures and controls are in place so the link removal effectively isolates the power and prevents inadvertent reconnection.

Portable equipment frames and enclosures used within the cell line working zone may be left ungrounded unless the cell line circuit voltage exceeds 200 volts DC or the frames are guarded; ungrounded portable equipment must be distinctively marked and use plugs and receptacles configured to prevent connection to grounding receptacles.

• See 1910.306(h)(3)(i) and 1910.306(h)(3)(ii).
• Use unique connectors and clear markings so ungrounded tools cannot be mistakenly connected to grounded circuits.

Circuits supplying power to ungrounded receptacles for hand-held equipment must be electrically isolated from other distribution systems and ungrounded, supplied through isolating transformers with primaries at not more than 600 volts and protected with proper overcurrent devices, have secondaries not exceeding 300 volts between conductors, and have approved overcurrent devices in each conductor.

• These detailed requirements are in 1910.306(h)(4)(i) through its subparts (A)–(D).
• Also, receptacles and plugs for ungrounded equipment must prevent grounding connections and be distinctively configured and marked per 1910.306(h)(4)(ii) and 1910.306(h)(4)(iii).

AC systems supplying fixed and portable equipment and exposed conductive surfaces within the cell line working zone need not be grounded; auxiliary electric equipment mounted on energized surfaces must be connected by multiconductor hard-usage flexible cord, wire/cable in suitable nonmetallic raceways or trays, or in metal raceways/trays with insulating breaks, and fixed equipment mounted on energized surfaces must be bonded to that surface.

• See 1910.306(h)(5)(i) through 1910.306(h)(5)(iii).
• Follow the allowed connection methods and bonding rules to avoid hazardous electrical conditions.

The main disconnecting means for a center pivot irrigation machine must be located at the point of power connection to the machine or be visible and not more than 15.2 m (50 ft) from the machine, must be readily accessible, and must be capable of being locked in the open position.

• These requirements are in 1910.306(i)(2)(i), 1910.306(i)(2)(ii), and 1910.306(i)(2)(iii).
• Ensure the disconnect is accessible for emergency shutoff and can be padlocked to prevent unauthorized re-energization.

Receptacles located within 4.57 m (15 ft), or 6.08 m (20 ft) for installations built after August 13, 2007, of the inside walls of the pool must be protected by ground-fault circuit interrupters.

• This requirement is in 1910.306(j)(1)(ii).
• Measure the shortest path the appliance cord would follow (without piercing a permanent barrier) when determining distance, per the note that accompanies the paragraph.

A single locking and grounding-type receptacle for a permanently installed pool recirculating pump motor may be located not less than 1.52 m (5 ft) from the inside walls of the pool; all other receptacles on the property must be at least 3.05 m (10 ft) from the inside walls, and where a pool is permanently installed at a dwelling unit you must provide at least one 125‑V, 15- or 20-A receptacle between 3.05 m (10 ft) and 6.08 m (20 ft) from the pool and not more than 1.98 m (6.5 ft) above grade.

• See 1910.306(j)(1)(i) and 1910.306(j)(1)(iii).
• Use the shortest cord path that would be used to connect an appliance when measuring distances.

Lighting fixtures, lighting outlets, and ceiling-suspended fans may not be installed over the pool or within 1.52 m (5 ft) horizontally from the inside walls of the pool unless the fixture is at least 3.66 m (12 ft) above the maximum water level or meets older-installation exceptions; lighting in the 1.52 m–3.05 m (5 ft–10 ft) zone must be protected by a GFCI unless installed 1.52 m (5 ft) above the max water level and rigidly attached to the structure.

• See 1910.306(j)(2) and 1910.306(j)(2)(ii).
• For fixtures installed before April 16, 1981 there is a limited allowance if they meet height and GFCI protection conditions described in the same paragraph.

Yes, but only for the limited time required to perform the necessary testing or positioning, and only after following the specific sequence of protective steps required by 1910.147(f)(1).

• OSHA’s Letter of Interpretation explains that temporary removal of lockout/tagout devices and re-energization is allowed for testing/repositioning under 29 CFR 1910.147(f)(1).
• The employer must clear tools and materials, remove employees from the hazard area, remove LOTO devices as specified, energize while providing effective employee protection, and then re-isolate and reapply LOTO devices if additional servicing is required. See the Letter of Interpretation at https://www.osha.gov/laws-regs/standardinterpretations/2024-10-21 for the full explanation.

Removable links are permitted as the disconnecting means, but employers should use clear labeling, written procedures, and controls to prevent accidental reconnection and to ensure that removing a link reliably isolates the supply.

• The permission to use removable links is in 1910.306(h)(3).
• Practical measures include lockable covers or padlocking provisions for link compartments, tagout procedures, and ensuring workers are trained and follow a documented isolation sequence.

Yes, the supply circuit disconnecting means is permitted to serve as the heating equipment disconnecting means where that supply circuit supplies only one piece of equipment.

• This allowance is in 1910.306(g)(1)(vi).
• Confirm that the circuit truly supplies only the one piece of equipment before relying on the supply disconnect as the equipment disconnect.

No; receptacles on circuits supplied by an isolating transformer with an ungrounded secondary may not be used in any other location in the facility.

• This restriction is in 1910.306(h)(4)(iii)(C).
• Also note they must be distinctively configured and marked per 1910.306(h)(4)(iii)(A)–(B).

Acceptable control systems include isolated and ungrounded control circuits, nonconductive rope operators, pendant pushbuttons with nonconductive supporting means and nonconductive surfaces or ungrounded exposed conductive surfaces, or radio control.

• These options are listed in 1910.306(h)(7)(ii) through (D).
• Choose a method that eliminates the risk of introducing hazardous conductive paths into the cell line working zone.

Detachable panels not normally used for access to energized parts must be fastened so they are difficult to remove—for example, by requiring the use of tools.

• The fastening requirement is in 1910.306(g)(1).
• Using tamper‑resistant fasteners or tool‑required screws helps prevent inadvertent or casual removal.

Yes. Each ride and concession must have a fused disconnect switch or circuit breaker located within sight and within 1.83 m (6 ft) of the operator’s station, and the disconnect must be readily accessible to the operator, including while the ride is in operation. See 1910.306(k)(5)(i) and 1910.306(k)(5)(ii).

• Make sure the device is visible from the operator’s station and can be reached quickly during normal operation.
• If sight or access is blocked by removable panels or temporary obstructions, correct that so the disconnect remains within sight and within 6 ft as required.

The enclosure must be lockable when it is accessible to unqualified persons. 1910.306(k)(5)(iii) requires a lockable enclosure in that situation to prevent unauthorized operation.

• If the disconnect is in an area the public or untrained staff can reach, provide a means to lock it.
• This ties to the broader requirement that service equipment not be installed where accessible to unqualified persons unless lockable; see 1910.306(k)(2)(i)(A).

Yes. Using a shunt trip device that opens the fused disconnect or circuit breaker when a switch in the operator’s console is closed is an allowed method of opening the circuit. See 1910.306(k)(5)(iv).

• Even when a shunt trip is used, employers must ensure procedures protect employees from hazardous energy during testing, repositioning, or control operations; OSHA’s Lockout/Tagout guidance explains that temporary energization and removal of energy control devices requires steps to protect employees (for example, clearing tools and personnel and following a prescribed sequence). See the interpretation on the minor servicing exception and temporary re-energization procedures (Minor servicing exception clarification).
• Document safe procedures for use of the shunt trip and ensure operators are trained on how and when the console control will de-energize equipment.

Yes. Branch circuits supplying underwater fixtures operating at more than 15 volts must have a ground-fault circuit interrupter (GFCI), and all electric equipment (including power cords) used with fountains and operating at more than 15 volts must be protected by GFCIs. See 1910.306(j)(4)(i) and 1910.306(j)(5).

• Underwater lighting fixtures may not operate at over 150 volts between conductors; see 1910.306(j)(4)(ii).
• For fixtures facing upward, the lens must be guarded to prevent contact, per 1910.306(j)(4)(iii).
• In practice, use GFCI protection rated for the circuit and ensure equipment is identified for underwater use where required.

Flexible cords and cables used outdoors at carnivals or fairs must be listed for extra-hard usage, listed for wet locations, and sunlight resistant; they must be continuous without splices between boxes or fittings, and where they run on the ground and are accessible to the public they must be covered with approved nonconductive mats arranged to avoid tripping hazards. See 1910.306(k)(2)(iii), 1910.306(k)(2)(vi), and 1910.306(k)(2)(viii).

• Do not use flexible cords with field splices between fittings or boxes; keep connectors off the ground unless they are listed for wet locations.
• Where public access exists, protect cords with nonconductive mats and secure routing so cables do not create trip hazards.
• If cords are subject to physical damage, provide mechanical protection as required by 1910.306(k)(2).

You must meet at least one of the listed conditions: (1) use interlocked supply connectors that can only be connected or disconnected when the supply is de-energized; (2) use listed sequential-interlocking connectors that make the equipment grounding connection first, then the grounded conductor (if any), then the ungrounded conductor, with disconnection in reverse order; or (3) provide a clear caution notice adjacent to the line connectors that instructs that connection and disconnection follow that same grounding-first sequence. See 1910.306(k)(4)(iv)(A)(1), 1910.306(k)(4)(iv)(A)(2) (and its subparts (i), (ii), (iii)), and 1910.306(k)(4)(iv)(A)(3).

• If you use paralleled sets of single-pole connectors as inputs, label them to warn about internal parallel connections per 1910.306(k)(4)(iv).
• Provide overcurrent protection and bonding as required for portable boxes; see the broader portable box requirements at 1910.306(k)(4).