Page 116 - Uninterruptible Power Supplies

Additional Information Relating to the Standby Supply Installation
114 Chapter Three

located in an open area it should be protected by lockable doors or
removable covers.
Unauthorized access should be prohibited to prevent persons tam-
pering with engine controls or adjustments and to avoid the dangers
that arise while it is running or when it unexpectedly starts. There
should be a rule that before any work on the set is commenced, the
starting sequence should be inhibited. Anyone who has experienced an
unexpected start while manually topping up a baseframe service tank
will realize the danger that can arise due to the sudden noise and
engine movement, and the involuntary reactions that occur.
Before any major work is undertaken on the generating set, the gen-
erator isolator or circuit breaker should be locked open, the key being
in the care of the senior person working on the set. This prevents any
possibility of the generator being connected to a mains supply, which
would cause it and the engine crankshaft to rotate. The overcurrent
protection may operate but too late to avoid any danger.
Large organizations usually have a set of safety rules including a
permit to work system, and if standby generation is added to a partic-
ular installation some additional rules may be necessary. Smaller orga-
nizations frequently get by with the minimum of safety rules. In such
cases it is recommended that some relevant rules be drafted and clearly
displayed within the engine room, or near the set if it is in an open area.
There should be a notice on the access door or doors making it clear
that access is restricted to persons who have been authorized to work
on the set or in the room. There should also be prominently displayed
a danger notice advising that the set starts automatically.
If the set is controlled from a remote station it is important that a set
of safety rules is agreed between the local and remote stations. Before
any start is initiated the rules must ensure that no person is working
on or near the set.
Within the engine room there should be emergency lighting which,
on loss of mains, provides illumination until power is restored. This is
sometimes provided by removable battery-operated hand lamps which
plug into wall-mounted base units. On loss of mains the lamps auto-
matically provide static illumination, and if removed from the base
units may be used as portable hand lamps. After use the lamp is
returned to the base unit where the battery is automatically recharged.

Bibliography
International Standards
ISO 3046, BS 5514—Reciprocating internal combustion engines. Performance. (For
details, see Chap. 1 Bibliography.)
ISO 8528, BS 7698—Reciprocating internal combustion engine driven alternating cur-
rent generating sets. (For details, see Chap. 1 Bibliography.)

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