29 CFR 1910.333: Selection and use of work practices

Question 1

A maintenance crew is about to service a motor control circuit on a conveyor. The electrician proposes to stop the conveyor with the push-button stop station and the safety interlock on the guard, then begin work without opening the main disconnect, because the controls show the circuit is 'off.' Under the standard, what is the correct response?

1. AAcceptable, provided a tag is hung on the push-button station
2. BNot acceptable; control circuit devices and interlocks may not be the sole means of deenergizing or substitute for lockout and tagging
3. CAcceptable, as long as the interlock and push button are both used together
4. DAcceptable for fixed equipment, since interlocks are permanent wiring methods

Question 2

A contractor's crew will repaint a rooftop sign that sits close to an uninsulated utility distribution line owned and operated by the local power company. The employer decides not to install guarding or insulation and instead wants the line deenergized for the job. Which action satisfies the standard before the crew starts work?

1. ALet the crew begin and deenergize the line only if a worker's tool or ladder comes within reach of it
2. BMake arrangements with the utility that operates or controls the line to deenergize and ground it before work starts
3. CHave a crew member visually confirm that the line is not sparking or humming, then treat it as deenergized
4. DHave the crew's own electrician open the building's main service disconnect, since this removes power from the nearby line

Question 3

A maintenance crew has opened and locked out the disconnect for a motor circuit and the nominal voltage is 480 volts. Before the crew begins work, the qualified person operates the start controls and confirms the motor will not restart. She then tests the motor terminals with a voltage tester and finds no voltage. A technician points out that the control circuit shares a conduit with another circuit that is still energized, and that other equipment feeds the same motor leads. What must the qualified person's test also do before the circuit can be treated as deenergized?

1. ABe witnessed by the employee who applied the lock, since only that employee can verify the circuit is deenergized
2. BDetermine whether any energized condition exists from inadvertently induced voltage or unrelated voltage backfeed, even though the circuit parts were deenergized and presumed safe
3. CBe replaced by a visual inspection of the lock and tag, because a lockout device is sufficient proof of a deenergized condition
4. DBe repeated at the start of each following work shift, because the test remains valid for only one shift

Question 4

A maintenance technician must replace a lamp holder in a switchgear room. Exposed energized bus bars run along the wall next to the work spot. The only ladder on hand is an aluminum stepladder, and the technician could easily lean the ladder against, or sway into, the bus bars while working. What must the employer do before the task goes ahead?

1. AProvide a portable ladder with nonconductive siderails, because the ladder or the employee could contact exposed energized parts
2. BAllow the aluminum ladder if the technician avoids wearing metal jewelry while climbing
3. CAllow the aluminum ladder if a coworker holds its base, since the bus bars are not being touched directly
4. DAllow the aluminum ladder as long as the technician wears a hard hat and safety glasses