Batteries/Ask George/ASTMSubcommittee 01

Q: Give some insight into the new ASTM subcommitee which will persue 42 Volt insulating systems?

1. What type of standards will the new subcommittee develop?

The subcommittee will be developing new test methods and standards for conducting pre-selection tests for use in road vehicle applications.  Specifically, the first new test being developed is the DC Comparative Tracking Index test.  The purpose of this test is to determine the susceptibility of the test material to resist or form a visible carbonized conducting path over its surface when subjected to DC voltages.  This new test method is similar to ASTM D 3638 except for changes in the electrical Voltage source and the aqueous contaminant.  

The second test being developed is the DC High-Current Arc Ignition test. The purpose of this test is to differentiate materials with regard to resistance to ignition from a DC High-Current Arc Ignition source.  It is similar to the test specified in UL 746A except for the change to a DC electrical supply source and other special modifications currently being developed.

2. Specifically, what type of professionals will use them?

Plastic and component manufactures will use these new standards when selecting materials for components in transportation applications.

3. Who initiated the new subcommittee?

ASTM Committee D09 initiated the new subcommittee.  

4. Why?

The subcommittee was initiated to conduct research related to electrical and insulating materials for use in 42 Volt systems and related road vehicle applications.  

5. Will the subcommittee include UL standards for 42-Volt applications
within the ASTM standards they develop?

Yes.  As indicated above, the new DC Comparative Tracking Index test being developed is similar to ASTM D 3638.  This new test will be specified within UL standards as well as the new DC High-Current Arc Ignition test.  Components that will be developed for the new 42Volt systems and other transportation applications may specify these new pre-selection test criteria in their respective end-product standards.  A new guidance document will also be developed so that pre-selection criteria can be applied to components for transportation applications.

6. ASTM manager Christie Sierk said the automotive industry plans to upgrade
to a 42 Volt electrical system. Why is the automotive industry upgrading to
a 42-Volt electrical system?

The automotive industry is making a transition in design from 14 Volt to 42 Volt electrification systems within automobiles.  Components that are currently mechanically operated through inefficient mechanical and hydraulic systems such as air conditioning, water pumps, oil pumps, heating, and solenoid operated engine valves will be converted to electrically operated systems. The resulting demands on electrical systems require upgrading from the traditional 12 V DC battery supply to a 36 V DC battery supply with a nominal 42 V DC charging circuit.  

6A. What are the concerns regarding an increase to 42 Volts?
Safety and the potential risk of fire and concerns in view of the increase in Voltage to 42 Volts DC.  Arcing at relays, switches and connections is a very big concern.  When a switch opens at 14 Volts, there is relatively no arc present.  However, at 42 Volts, the arc is more pronounced and the potential for fire has significantly increased.  Therefore, it is important that standardized pre-selection tests be developed in order to appropriately select materials for use in applications where the potential for arcing exists.

7. What type of electrical system do these vehicles use now?

Automotive vehicles currently use 12 Volt DC battery (14 Volt charging system).

8. Does it have anything to do with converting to the metric system?


9. What type of vehicles will use the 42-Volt system?  Personal cars, SUV's, and trucks, as well as commercial trucks and buses? Will it apply to new cars only, or will existing vehicles typically receive the new 42-Volt system?

At the present time, the 42 Volt systems will apply to hybrid personal cars and SUV's, but note that there are also many other vehicles such as trucks and buses that operate at different Voltages.  Hybrid vehicles contain parts of both gasoline and electric vehicles and are presently being produced with more companies getting ready to introduce more new models in the next few years.       

10. What type of electrical system is commonly used now?

For personal cars, the operating Voltage is 12 Volts, 14 Volts charging.

11. Will the upgrade to a 42-volt system apply to American-made vehicles or
foreign vehicles, too?

The upgrade will apply to domestic and foreign vehicles.

12. Would you like me to ask for additional participation on the
subcommittee? If so, name specific representation you'd like from a particular
sector or profession.

We should ask for additional representation from component manufacturers and plastic suppliers that are directly involved in the automotive sector.

13. What are the professional backgrounds or specialties of the members on
the subcommittee now?

We currently have participation from plastic and component suppliers from the automotive sector.  (Company and individual name are excluded to avoid the appearance of promoting certain companies.)