General Information
(
Voltage)2
1)
Power Dissipation =
Resistance in ohms
Electrical Resistance Tests
for Hose and Hose Assemblies
1.0
Purpose
This procedure specifies methods for performing electrical resistance tests on rubber and/or plastic hose and
hose assemblies.
2.0
Scope
These procedures are intended to test electrical conductive, antistatic and nonconductive (insulating) hoses, along with
electrical continuity or discontinuity between fittings.
Warning
Hydraulic hoses used on power and telephone mobile equipment should
be tested to SAE 100R8 requirements.
3.0
Definitions
3.1
Antistatic Hose - Antistatic hose constructions are those that are capable of dissipating the static electricity buildup
that occurs during the high velocity flow of material through a hose.
3.2
Conductive Hose – Conductive hose constructions are those that are capable of conducting an electrical current.
3.3
Direct Current (DC): Flow of electrical current in one direction at a constant rate.
3.4
Electrical Conductivity: A measure of the ease with which a material is capable of conducting an electrical current.
Conductivity = 1/Resistance.
3.5
Electrical Resistance: Property of an object to resist or oppose the flow of an electrical current.
3.6
Non-Conductive (Insulating) Hose: Non-conductive hose constructions are those that resist the flow of
electrical current.
3.7
Ohm’s Law: The electrical current, I, is equal to the applied voltage, V, divided by the resistance, R. In practical terms,
the higher the electrical resistance at a constant voltage, the lower the electrical current flow through an object.
3.8
Ohm: The amount of resistance that limits the passage of current to one ampere when a voltage of one volt is
applied to it.
4.0
Apparatus
4.1
Test Instruments: All test instruments shall have a gauge reliability and reproducibility (R&R) of less than 30%. Some
instruments made to measure high electrical resistance may have an internal protection circuit built in which will cause
test
errors in the less than one megohm range.
During the test, no more than 3 watts (W) shall be dissipated in the specimen, to prevent erroneous results due to effects
of temperature. The power dissipated shall be determined by the square of the open-circuit voltage divided by the mea-
sured resistance, see formula 1 (Power Dissipation).
To determine the electrical resistance of non-conductive hose, the test should be made with an instrument designed
specifically for measuring insulation resistance, having a nominal open-circuit voltage of 500 volts D.C., or with any other
instrument known to give comparable results. For measuring electrical discontinuity, a 1,000 volt D.C. source may be
used instead of a 500 volt D.C. source.
For hoses with a conductive tube or cover, the resistance values obtained may vary with the applied voltage, and errors
may occur at low-test voltages. As a starting point, an ohmmeter (9 volts) can be used. For tests requiring measurement
of electrical continuity between end fittings or through continuous internal or external bonded wires, the instrument
used shall be an ohmmeter (9 volts).
4.2
Electrodes and Contacts: When the test procedure calls for contact with the hose cover, electrodes shall be formed
around the outer circumference of the hose as bands 25mm +2mm, 0 mm (1" +1/16", 0") wide by applying silver lacquer/
conductive liquid and metallic copper foil tape (i.e. 3M Scotch Brand) as shown in Figure 6-1. When a conductive silver
328
Appendix
C
Air & Multipurpose
General Purpose
Heavy Duty
Push-on
Chemical Transfer
Cleaning Equipment
Food
Transfer
Washdown
Marine
Material Handling
Abrasives
Bulk Transfer
Cement & Concrete
Mining
Petroleum
Aircraft Fueling
Dispensing
Dock
Transfer
Spray
Steam
Vacuum
LPG Delivery
Water
Discharge
Suction & Discharge
Washdown
Welding
Coupling Systems
Equipment
Appendix