IBM 390E manual Electrical Safety

Electrical Safety

Observe the following rules when working on electrical equipment.

Important

Use only approved tools and test equipment. Some

hand tools have handles covered with a soft material that does not insulate you when working with live elec- trical currents.

Many customers have, near their equipment, rubber floor mats that contain small conductive fibers to decrease electrostatic discharges. Do not use this type of mat to protect yourself from electrical shock.

ŸFind the room emergency power-off (EPO) switch, disconnecting switch, or electrical outlet. If an elec- trical accident occurs, you can then operate the

switch or unplug the power cord quickly.

ŸDo not work alone under hazardous conditions or

near equipment				that	has		hazardous voltages.
Ÿ Disconnect		all	power		before:
–	Performing		a	mechanical			inspection
–	Working	near		power		supplies
–	Removing	or		installing		main units

ŸBefore you start to work on the machine, unplug the

power	cord. If	you	cannot	unplug	it,	ask	the	customer
to power-off the wall box that supplies							power	to the
machine	and to	lock	the wall	box	in	the	off	position.

ŸIf you need to work on a machineexposedthat has

electrical circuits, observe the following precautions:

–Ensure that another person, familiar with the power-off controls, is near you.

Attention: Another person must be there to switch off the power, if necessary.

–Use only one hand when working with powered-on electrical equipment; keep the other hand in your pocket or behind your back.

Attention: There must be a complete circuit to cause electrical shock. By observing the above rule, you may prevent a current from passing through your body.

–When using testers, set the controls correctly and use the approved probe leads and accesso-

	ries	for	that		tester.
–	Stand	on	suitable			rubber	mats	(obtained		locally,
	if necessary)				to	insulate	you	from	grounds		such
	as metal floor strips and machine frames.
Observe		the	special			safety	precautions		when	you
work	with	very		high		voltages;	these instructions				are in
the safety sections of maintenance information. Use
extreme		care		when	measuring		high	voltages.

12 ThinkPad 390E