# Wiring help



## 106389 (Aug 11, 2007)

I am wanting to use one of the CBE fused spurs which is rated at "10amp 230v", to connect a 150w inverter instead of the supplied lighter plug which would be 15amp 12v, would this be ok/safe?, Steve at Marcle Leisure says it will be fine but I always like to play safe & double or even treble check.
THANKS in anticipation.
Paul

Edit: Steve @ Marcle Leisure has just emailed me again, he had misread my email, now sounds like the CBE fused spur would not be suitable.


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## Fatalhud (Mar 3, 2006)

He's wright
you would be pulling around 12.5 amps at 150 watt

Alan H


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## safariboy (May 1, 2005)

I think that I must have misunderstood this post. If it really is a 240V 10A fused spur it would be totally unsuitable. It would instantly burn out the inverter. The voltage is far too high and it would instantly burn,out the inverter. Please tell me that I have misunderstood your post!

Safariboy.


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## 106389 (Aug 11, 2007)

Hi Safariboy,

It is not wired to 240v, The rating of the CBE fused spur is 10amp 230v,
but I was wondering if it would be ok/safe to use as a 12v fused spur instead of 240v, which would be 12v 15amp.

THANKS Paul


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## pippin (Nov 15, 2007)

CBE?


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## 106389 (Aug 11, 2007)

pippin said:


> CBE?


Hi Pippin,
It is the name/make of the electrical sockets & accessories that I think you get in most motor-homes nowadays, Do a Google for "CBE sockets" & you will soon see what they are, sorry I dont know how to add links to websites etc.
Paul


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## wobby (May 1, 2005)

If you are talking cable capacity the the answer is yes.

10 amp at 230 volt = 2300 watts

15 amp at 12 volt = 1800 watts

Your question is a little bit confusing though. Its always best to go for a large cable to supply an inverter it can never be to large! but to small and you risk an electrical fire on a previous thread I advised using a cheap set of Halford jump leads these would be plenty big enough 

Wobby


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## 106389 (Aug 11, 2007)

Hi Wobby,
Its not the cable I was questioning (I used approx 4m max length of 40amp rated cable). it is the CBE switched fused spur that I was hoping to wire the inverter into instead of using the 12v lighter plug & socket, I recon it is not suitable, that is why I questioned it on here after Steve initially said it was suitable, I will probably stick with just plugging/unplugging it into the lighter socket (that I wired with the 40amp cable as mentioned above).
Paul


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## Fatalhud (Mar 3, 2006)

As i saw it Paul was wanting to use a spur that has a normal rating of 10Amp and is rated upto 230volt
He is using it with 12volt but is questioning if the spur was ok to run 150 watts at 12volt through it

Does it have to be CBE or could you not use a standard type 13amp switch spur
Alan H


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## 106389 (Aug 11, 2007)

Hi Allan,
You've got the gist, I was wanting to use the CBE as I have a blank space just in the right place for it, they have a unit with 4 fuses I could use but I only need one fuse, so it seems a bit daft, there switch fused spur would have been ideal as I could use the switch to totally isolate the inverter, because when you switch the inverter of using the inbuilt switch it still draws some power from the battery.


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## gaspode (May 9, 2005)

As I see it your main problems are:
1) The spur is only rated at 10 amps and you will pull in the region of 14 amps if you fully load the inverter (taking losses into account).
2) If I understand correctly, you intend to use a switch rated for AC on a DC circuit. DC is a much more difficult current to switch and will cause burning at the switch contacts due to back EMF voltages generated when you switch the inverter off. DC switches are normally rated at a much lower current than AC switches for this reason. If your switch/spur is rated at 10 amps for AC I wouldn't use it for more than 5 amps on DC irrespective of voltage rating.

Result - unsuitable in my opinion.


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## sallytrafic (Jan 17, 2006)

gaspode said:


> As I see it your main problems are:
> 1) The spur is only rated at 10 amps and you will pull in the region of 14 amps if you fully load the inverter (taking losses into account).
> 2) If I understand correctly, you intend to use a switch rated for AC on a DC circuit. DC is a much more difficult current to switch and will cause burning at the switch contacts due to back EMF voltages generated when you switch the inverter off. DC switches are normally rated at a much lower current than AC switches for this reason. If your switch/spur is rated at 10 amps for AC I wouldn't use it for more than 5 amps on DC irrespective of voltage rating.
> 
> Result - unsuitable in my opinion.


gaspode is right when it comes to this sort of circuit reference to Watts is largely irrelevant its dc amps wot counts.


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## 106389 (Aug 11, 2007)

Thanks Gaspode & Frank,
Looks I will have to stick with just plugging/unplugging it into the lighter socket, 
Paul


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## sallytrafic (Jan 17, 2006)

You're lucky if your cigarette lighter can take more than 10A. The one that I installed near the battery in the back can but I don't think the one in the dash could, its only fused at 10 anyway.


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## 106389 (Aug 11, 2007)

sallytrafic said:


> You're lucky if your cigarette lighter can take more than 10A. The one that I installed near the battery in the back can but I don't think the one in the dash could, its only fused at 10 anyway.


As I stated earlier the lighter socket is one that I put in specifically for the inverter using approx 4m length of 40amp rated cable, directly wired to the battery with a 15amp in-line fuse, which I think is overkill, the lighter socket itself I cant remember exactly what it was rated at but it was at least 16amp.


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## sallytrafic (Jan 17, 2006)

PaulandJackie said:


> sallytrafic said:
> 
> 
> > You're lucky if your cigarette lighter can take more than 10A. The one that I installed near the battery in the back can but I don't think the one in the dash could, its only fused at 10 anyway.
> ...


sorry missed that :roll: but it will do as a reminder to others.


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## pippin (Nov 15, 2007)

Don't forget that lighter sockets were designed for, well, lighters!

A lighter draws a lot of current but for only a limited amount of time.

I would be checking very carefully for any signs of warming up and possibly overheating of any lighter socket being used with a significant load of amps for an extended period of time.

Their electrical construction does not look very heavy-duty to me, very poor contact resistance characteristics generally.


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## 106389 (Aug 11, 2007)

pippin said:


> Don't forget that lighter sockets were designed for, well, lighters!
> 
> A lighter draws a lot of current but for only a limited amount of time.
> 
> ...


If a lighter socket might not be suitable to power small inverters, why do the company's who manufacture inverters get away with selling them with plugs for the lighter socket, with all the regulations nowadays, if it wasn't safe, I thought they would not be able to market them as such, I know they warn you that you should make sure the wiring is heavy enough.


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## pippin (Nov 15, 2007)

There are simply no regulations or standards covering this sort of thing.


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## 106389 (Aug 11, 2007)

I have decided to use one of the CBE blanks , put a dash mount blade fuse holder & a 16amp toggle switch into the blank, & wire the inverter into them. so it is fused at this end as well as the battery end & I can use the switch to isolate the power from the inverter completely or I could even remove the fuse if needed.
Anyone got any reasons why I shouldn't do it this way.
Thanks in anticipation Paul


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