Piper Comanche PA-24 Service Manual page 225

TABLE IV-III. ELECTRICAL BONDING RESISTANCE INDEX
Component
Engine Mount(s)
Generator(s)
Ailerons
Elevator / Stabilator
Rudder
Alternator(s)
Trim Tab(s)
Conventional Hinge
Piano Hinge
Instrument Panel Inserts
Exterior Lights Mounted on Non-Conductive Material
Avionics 'Black Boxes'
NOTE: Harnesses should be installed and connected for this check, internal chassis
wiring through the connector to ground is permissible for this grounding.
Battery Ground Point
Static wick mounting plates (TCO Model B-4) P/N 452-094
NOTE: Where jumper wires or cables are used to accomplish a proper bond, resistance between the
jumper terminal and the component or structure shall not exceed .001 ohms. The controlling
points for measuring resistance will be within the limits of the cleaned area to be bonded and
within 1/4 inch of the exterior limits of the bonding jumper terminal or material called for in
the bill of materials of the drawing.
Resistance to ground will be measured from wire terminal to structure for electrical /
electronic equipment not internally grounded and from mounting flange to structure for
equipment that is internally grounded.
COMPONENT SURFACE
28 VDC SOURCE
-
+
04/01/09
PIPER SENECA SERVICE MANUAL
VOLT METER
MV
BONDING STRAP
A
AMMETER
Figure 4-7a. Millivolt Drop Test
1E18E
Maximum Allowable
Resistance Value in Ohms
AIRCRAFT STRUCTURE SURFACE
Adjust rheostat (R1) so that ammeter (A)
reads 10 Amps.
Resistance in milliohms is then the reading
on the volt meter (i.e. - millivolts (MV))
divided by the amps (10) set on the
ammeter. For example, where MV equals
30:
R1
30 MV
10 AMPS
.003
.010
.003
.003
.003
.010
.003
.010
.010
.003
.003
.010
1.00
= .003 OHMS RESISTANCE
IV - STRUCTURES