Automotive 48VDC needs to be isolated?

Hi,
For an automotive bus, if you have say a 120Vdc (or higher) bus from the [source] on the car...and you want to convert it to 48Vdc, 100A, then would you need isolation? I assume its a regulatory thing?

Flyback said:

Hi,
For an automotive bus, if you have say a 120Vdc (or higher) bus from the [source] on the car...and you want to convert it to 48Vdc, 100A, then would you need isolation? I assume its a regulatory thing?

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If you assume that why ask here? You have a habit of doing this, asking some random people online to give you answers that in the end are controlled by laws. Hell of a way to run a business.

I thought about isolating it, but it seems a waste of time, because the chance of someone getting shocked with >48VDC is very very low.
With a non isolated converter, you can put in protection, to disconnect the >120vdc if a fault occurs.
And lets face it, the >120vdc source is still on the car anyway, even if you isolate.
So if theirs a crash.....the isolation transformer possibly isnt going to protect you from the >120VDC anyway.
I would have thought a reasonable , non-isolated solution could be found.

You might say theres a danger to service engineers..but ive worked on non isolated high voltages above 400VDC and no one said that i was in danger...no regs against it.
I was regarded to be a "trained person".

A customer isnt likely to come into contact with >48VDC with suitable protection, even if non isolated.

The high voltage side is normally floating for safety and fault detection. That is law for any hybrid or EV system operating above 60V.

Anything that runs off that must therefore also be fully floating to not affect the safety systems, or fully isolated.

rjenkinsgb said:

The high voltage side is normally floating for safety and fault detection. That is law for any hybrid or EV system operating above 60V.

Anything that runs off that must therefore also be fully floating to not affect the safety systems, or fully isolated.

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^^^^ this

Flyback said:

I thought about isolating it, but it seems a waste of time,

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But you missed my point. There are probably rules that cover what you doing, so why not just ask the governing body in the country your product will be sold in??? In another of your similar threads you said it costs too much to get the rule book (or what ever it was you didn't have) but would that cost be anywhere near what a lawsuit would be?