The Pacific commercial advertiser. [volume] (Honolulu, Hawaiian Islands) 1885-1921, 1908-05-17

most sure to break down the insulation
| of the system in such a manner as to
cut off the current automatically. 1t is
doubtful if there has been a fatal case
from this cause in the entire country
during the past year. Wires entering
the building underground may, through
arrangement of the system, carry a
| dangerously high voltage; there is much
! less chance of this than with overhead
wires, the probability of such a thing
occurring being so slight that it may be
disregarded.
Motors are almost invariably oper-
ated on either ITO, 900 or 500 volts, volt
| age or 10 per cent higher being in
| cluded in the general figures given. 1t
| is well to avoid touching any part of
| the motor when the controlling switch
i is being opened, as at that particular
| instant higher voltage may momentar-
| lily occur. At 500 volts the current be-
| gins to be dangerous; the circuit is
| nearly always grounded to a greater or
| less extent, and unless one is careful
| where he stands a shock Is received on
/ touching the wires This is because the
| high pressure forces current through
! distractions in a greater volume than a
| low pressure; the pipe filled with fine
| sand would allow hardly any water to
flow at low pressure, but might pass a
considerable quantity when the pressure
| is increased two or four fold. and a thin
layer of clay that would stop all flow at
low pressure might be broken away by
the higher pressure. Standing upon a
clean, dry board one inch thick will
prevent any possibility of a shock, so
| long as we touch but one wire at time
and are careful not to bring the hand
or body in contact with any external
| object that might give the current a
path to the ground Where only slight
| ground exists a slight shock may be re-
| ceived in the same way as with the
| 110-volt circuit. 1t is not the voltage
| that we feel, but the amount of current
| (amperes) that is forced through the
| body: one one hundredth of an ampere
passing through the body will give the
same sensation from 500-volt circuit
| as it does from 4 110-volt The fact
| that one has received a shock from a
| 500-volt circuit that did not prove pain
| full is not a sign that the next one will
| be equally harmless. The following ex-
J periments have been tried. involuntar-
! lily, by a great number of people:
Touch one side of the circuit lightly
with the fingers while making contact
| with the other side either through a
! ground or by actually touching it; the
sensation is similar to receiving a vio-
lent blow in the chest; small burn
! that is deep. but not painful will be
| found on the finger where contact was
| made. Make better contact. as by
| touching the circuit with a piece of
| metal held firmly in the hand and the
blow will be strong enough to knock the
experimental down. 1t is probable that
no burn will result, as the current has q
large surface through which to enter
the hand; in rare eases the person may
become unconscious for a short time
J Grasp the wire firmly in the hand. anC
for a time at least it will be impossible
to release it. Serious burns are made
where the wire touches the hand. anC
unless the victim succeeds in wrenching