14 SPECIAL CONSIDERATIONS (continued)
The suitability of the concrete for use with a holiday detector can be
checked using the following:
1
Make a high voltage return contact by hammering a nail or similar
into the concrete.
2
Attach the earth signal return cable to the nail, set test voltage for
the thickness of coating, or in the range 3 kV - 6 kV if the test
voltage is not known and set the sensitivity to maximum
(5 µA current).
3
Place the probe on uncoated concrete about 4m (13ft) from the
nail.
If the alarm sounds, then the concrete is sufficiently conductive. If the
concrete is too dry, i.e. the alarm does not sound, then it is unlikely that
the holiday detector will be a suitable inspection method.
14.3 LENGTHENING THE EARTH SIGNAL RETURN CABLE
Lengthening the return lead by connecting several leads together may
invalidate the EMC performance of the equipment.
15 ERROR MESSAGES
Under certain conditions the instrument will display error messages.
These messages are normally cleared by pressing one of the keys.
The cause of the error will be indicated by the message and should be
corrected before proceeding, see Table 4.
Error Message
SPARKING TO
CASE
00
d
Or your local Elcometer supplier.
en-25
R
Causes
Current is returning from
the probe to the instrument
via a route other than the
earth signal return cable.
High voltage probe handle
device error.
TABLE 4
Action to Take
Check that all cables are connected
correctly.
If the instrument is in contact with the
item being tested, move it to a
location isolated from the item.
Ensure that you are not touching the
probe against the metal connector at
the end of the high voltage handle
connecting cable.
Remove high voltage probe handle
and ret. If error persists, contact
Elcometer .
d
www.elcometer.com