Hybrids and Orange- What's Up?

Once again, it is worth reviewing the changes that auto manufacturers are going through regarding color-coding of electrical cables in new vehicles. The question from a Long Island firefighter that 'sparked' this Forum message is below.

"Hi Ron, just a quick question if you can. Is the color orange still the only color being used for the power supply on hybrid vehicles ?

To answer the question, I recommend that the July 2007 University of Extrication article be reviewed. The focus of that article was the color changes occurring with hybrid high-voltage cables.

Up until model year 2006, all hybrid vehicle high-voltage electrical cables and connectors were ‘traffic cone’ orange. This was such a great thing. If it was high-voltage, it was orange. Well, much has changed since the 2006 models rolled off the production line. Manufacturers now identify voltages of different wires on a vehicle by color. Colors such as orange, blue, and yellow are now part of the identification plan. It's primarily for those working on a vehicle; either in a repair shop or doing after-market installations of electrical equipment.

Regarding the issue of hybrid vehicle power cables, there are 300-volt hybrids all the way down to 36-volt hybrid systems. So, to comply with the industry-wide power cable color schemes, we no longer have all high-voltage hybrid electric cables and connectors colored orange. It is now possible to have hybrid high-voltage wiring color-coded orange, bright blue, or even yellow. Some hybrid vehicles use two different colors for their high-voltage electrical system on the same vehicle depending on what current flows through that line.

What is the absolute bottom line for responders? Consider all cables as having lethal power inside them until proven otherwise. Black, red, blue... it doesn't matter. They should all be respected at an incident scene.

For hybrid electric vehicles, there is still one truth that holds up for responders. All orange cables on a gasoline-electric hybrid vehicle are high voltage. Not all high-voltage cables however on a hybrid are orange! Raise the hood and see for yourself.

It's an interesting read.

And with interest this week I read in the local community newspaper of a mechanic that is now converting petrol powered cars into hybrids.

I can assure you there would be no standards being met there in terms of colour coding of cables, etc and certainly no ERG for responders....

i would also like to add that in the event of responding to a car fire of a hybrid vehicle, in many cases it is not wise to use a halligan to gain access to the engine compartment. Many fire depts, like to drive the spike on the halligan through the hood to pry up the corner to gain access to the engine compartment. This practice would likely cause penetration into the inverter/converter, which is located directly under the hood, in a position typical of a 12 volt battery. In many Toyota vehicles the inverter will convert voltage from the hv battery packs to 3-phase voltage (245volts DC to 650 volts 3- phase AC)to power the electric drive motor, and accessories such as air conditioning . Puncturing that inverter with a halligan will as we like to say "set you free".

cut the 12v and you kill all high voltage because the circuits are normally closed.

I have been known to look right at things and not see them. Where is the article that Ron is referring to? I cannot find it on the site at all.

charlie you are correct , but just like with airbags there are capacitors in these vehicles that can take up to 10 minutes to drain. the other issue is where are the batteries . in the 08 toyota prius the 12 volt battery is located in a compartment ,within a compartment, (similiar to where you would find a spare tire). in some late model GM sedans the battery is located under the rear seat. it is important that when training we spend time famailiarizing ourselves with how specific vehicles are laid out.

I just wanted to note that in some situations disconnecting the battery cables WILL NOT shut down the high voltage. If the vehicle is in the run mode, the relays at the high voltage battery are being held shut from the voltage being generated from the vehicle, not the battery. It is importand that you disconnect the battery and push the power button on the dash to make sure the vehicle is powered down. Make sure that all of the lights on the dash are out.

This situation is similar to disconnecting the battery on a regular gasoline vehicle. The vehicle continues to run powered by the voltage created by the alternator.

I have pictures of a Toyota Prius where we did extensive testing on the hybrid system that shows the battery cables disconnected and 201V running through the high voltage cables.

SOTA4311
Hey just wondering how you did your tests. I am very interested in your results and test methods. Your results debunk the current teaching as to shut down the 12 volt system you shut down the HV system. Please post more details on your methods and your results. Thanks!!!

gober88,

you can also take a look at the Toyota and Lexus Emergency Response Guides to see that SOTA4311 is right. Why the hell should they recomend to disconnect the battery AND push the start/stop button or pull a fuse when disconnecting the 12 V battery is all that is necessary?

The testing that we did was on a 2006 Toyota Prius. We powered up the vehicle and tested to make sure that 201V was running through the orange cables under the vehicle. We connected a DVOM (Digital Volt Ohm Meter) to the point where the high voltage cables attach to the relays within the high voltage battery box. Then we disconnected the 12V battery. With the 12V battery disconnected we noted that the relays remained closed and 201V continued to flow through the cables from the high voltage battery box to the front of the vehicle. Whenever we pushed the power (Start/Stop) button on the dash the relays opened and cut off the flow of high voltage with the battery connected or disconnected.

We also used a hydraulic cutting tool to cut through the high voltage cables under the vehicle while the vehicle was powered up and 201V was running through the cables. As soon as we started cutting the cables the system was shut down and no electrical current entered the tool. When we inspected the high voltage orange cables we found that they were actually 2 cables in one. There is an inner cable that carries the high voltage current that is typically aluminum wire that is covered with an orange plastic insulation. Outside of this is a braided copper wire that is wrapped around the inner cable that acts as a ground fault for the system. This is also covered with an orange plastic insulation which is what you see when you look at the cables. The braided cable is designed to detect any leakage of voltage from the inner cable and to detect any electrical short in the system. When we cut through the cables we found that the cutter blades make contact with the ground fault wire first and then as you continue to cut they make contact with the inner high voltage cable which shorts out to the ground fault wire and opens the relays at the high voltage battery shutting down the flow of current through the cables. No voltage was ever detected at the tool. We also found that the system is designed so that voltage from the capacitors cannot back feed through the cables to the battery.

We also found that when we cut through the fully charged orange cables under the vehicle just behind the front seat (the position that we felt was most probable to be accidentally cut during rescue operations) that both the high voltage system and the 12V system were shut down. When the cable was shorted the high voltage relays were opened and the fuse at the positive battery cable was blown. Nothing on the vehicle was powered anymore including lights, flashers, horn etc.

Now for those of you that can’t wait to attack and criticize others on this forum I make the following statement:

WE DO NOT RECOMMEND OR ENDORSE EVER CUTTING, HANDLING, OR WORKING CLOSE TO A HIGH VOLTAGE CABLE ON A HYBRID VEHICLE. WE ALWAYS RECOMMEND THAT YOU FOLLOW THE VEHICLE MAKERS RECOMMENDATIONS FOR HANDLING A HYBRID VEHICLE. WE DID NOT TEST EVERY VEHICLE IN THE WORLD, ONLY A 2006 TOYOTA PRIUS. WE ARE NOT SUGGESTING THAT CUTTING THE ORANGE CABLES IS A SAFE PROCEDURE AS THERE CAN BE CATASTROPHIC FAILURES OF ANY SYSTEM, SO TREAT ALL HYBRID VEHICLES WITH CAUTION.

If you would like any additional information on hybrids or alternative fuels vehicles please email me at todd@sceneoftheaccident.org

SOTA. what if anything happened when the cuts were made on 'hot' HV lines?
thanks