0V To Earth?

[Mr Fuxit]

On a vehicle trailer, which is supplied with 230v AC, to the Earth of which the chassis and all metalwork is bonded, a 12V transformer/rectifier is tapped off to feed a 12V DC unit, the  Neg/0V return of which is through the chassis. This has worked for years; it has never been a problem, and no-one has suggested it is a problem. However, I can find nothing in the Regs that helps. Perhaps i should add, that the 230V AC supply is to the latest specification and is compliant in every way. 

Is there any reason this should not be used?

 

[Andy™]

0v to earth with reference to what? exactly what is your question? hard to understand it

 

[matt.leung]

+1

 

[Mr Fuxit]

I'll try again.

1  There is a vehicle trailer which is used as an office

2  It is supplied with 230v AC, from a fully compliant source, in order to to be able to have lights

3  The trailer chassis and all metalwork thereon are Earthed through the supply

4  There is a CU in the trailer

5  From the CU, a supply goes to a transformer/rectifier unit where the voltage is reduced to 12v DC

6  The t/r unit is earthed

7  The 12v DC drives a small load, and the return, as in cars, is through the chassis (which is Earthed) as there is no other way to do it

8  As I understand it, a DC circuit has +ve voltage on one side of the load, and on the other side of

    the load has Zero volts relative to the +ve side. This means that the DC circuit is completed through the Earth

9  This has worked for quite some time with no problems

10  My question is as before; is there any reason that this system should not continue to be used? 

 

[kme]

Ah.

You`re  concerned that the earth potential of the chassis, wrt mains voltage, is ALSO the negative ground of the 12V?

If so - its not really an issue; as long as the 12V supply is correctly set up - Its no different to installing an inverter in a car / van; and having the earth of the inverter onto the vehicle chassis. 

 

[ProDave]

It's what caravans and motorhomes do all the time.  No problem at all.

 

[Mr Fuxit]

Thanks very much, gents!

 

[kme]

Green "scoob" button.......?/????

You`re welcome!

 

[Badger]