# Fuse keeps blowing



## RichardD (Sep 14, 2009)

I've just added an extra cigarette socket in the cupboard where the TV is to take the Inverter to run the Sky Box. I have put it in parallel with the existing Rapido 12v DIN socket. Used crimps on the wires as the socket came with push on blades. Everything looked in order and the socket had 12v on it when the power was switched back on. 

When I plugged the new Ring Inverter in it blew the fuse which was in the cigarette plug supplied with the unit. I thought it was a faulty unit and had it replaced.

The replacement Inverter was delivered today but this time it did not have a fused cigarette plug. Plugged it into the new socket and it blew the main fuse in the CBE distribution box.

I then plugged the Inverter into a 12v live socket on the dashboard coming from the vehicle battery and it worked fine and powered up a 60W table lamp.

I have to think it is a problem with the socket, but how could the fuse going to the Inverter blow? The Inverter was not even switched on or had a load on it.

Any ideas guys?

Richard


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## ched999uk (Jan 31, 2011)

I know it may sound silly but are you 100% positive that the inner centre of the new socket is 12V and the outer bit is 0V?
Some devices will blow their fuse or internal fuse if they are connected the wrong way round!


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## RichardD (Sep 14, 2009)

Thanks for that thought, I'll put my multimeter on it tomorrow before I start to take it all apart.

Richard


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## RichardD (Sep 14, 2009)

But thinking about your reversed polarity suggestion again, the Inverter was not switched on. I just plugged it in and it blew the fuse.

So in my eyes the only possible short circuit has to be via the socket when the plug was inserted, but why did the Inverter fuse blow?

Richard


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## ched999uk (Jan 31, 2011)

I do know of some pieces of equipment that have a reverse voltage protection diode inside, directly connected to the power cables where they connect to the circuit board. So it doesn't need to be powered on to blow the fuse. It's there to protect the sensitive electronics, blowing the fuse is an easy way to show consumer that something is wrong.
So I can understand how the inverter fuse could blow even though it was not switched on.

I assume that the inverter draws a current that the CBE distribution box can handle? A 120watt inverter will probably be pulling over 10amps more likely 12amps on full load.


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## RichardD (Sep 14, 2009)

The CBE circuit is fused at 20A, but I will only be using the inverter on a 30W Sky Box.

Something else that appears to be odd. On the same circuit and fed from the CBE distribution box I also have the Vision 530 signal amplifier and the Maxview satellite control box. Both 'on' LEDs are still glowing!! They go off when I pull out the connector which has the socket feed wires inside the CBE box. 

Very odd!!

Now coming to think about it, when I checked the wiring with my multi-meter before putting all the Rapido panelling back in place, the voltage gradually crept up to finally reading 13.4v (Battery is currently on EHU). 

Just about to get out in the van and start investigating.

Richard


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## RichardD (Sep 14, 2009)

Thanks chad, right first time! I used red crimps on the wire and didn't check carefully enough as to which crimp was on which terminal. Everything now works OK.

Plugged Inverter in and powers up OK, but I didn't realise that the fan would be running all the time!! It is very noisy.

I'll start a new thread on this subject.

Richard


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## ched999uk (Jan 31, 2011)

Glad you got it sorted. Happy watching.


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