# Electric Hook Up Plugs



## cater_racer (May 1, 2005)

At Silverstone yesterday I was in the outer paddock and the EHU was via a new kind of socket to me, it was much larger than the normal blue 16 A HU.

It was white with 4 pins, 3 phase maybe? fortunately a neighbour had one, with a tail to three normal blue 16A sockets, and one was spare.

So my microwave and toaster were ok. But I'd like to have one of these in my arsenal for future use, any ideas on where these things are sold?


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## clodhopper2006 (Aug 13, 2006)

cater_racer said:


> At Silverstone yesterday I was in the outer paddock and the EHU was via a new kind of socket to me, it was much larger than the normal blue 16 A HU.
> 
> It was white with 4 pins, 3 phase maybe? fortunately a neighbour had one, with a tail to three normal blue 16A sockets, and one was spare.
> 
> So my microwave and toaster were ok. But I'd like to have one of these in my arsenal for future use, any ideas on where these things are sold?


Hmmm, 4 pin would normally be three phase and earth. 5 pin would be three phase neutral and earth. I hope they weren't using the earth as a neutral.


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## cater_racer (May 1, 2005)

I think I've found the plug see #260407722979 on eBay.

Would it be star configured 3 phase?


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## clodhopper2006 (Aug 13, 2006)

It's just a 3 phase and earth plug. No neutral pin. Star or Delta hasn't got anything to do with a plug or socket. The term star refers to thewiring within an appliance such as in a motor.
If you were obtaining single phase 230v through this plug then you were using earth as a neutral. Pretty outrageous really.


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## pippin (Nov 15, 2007)

You would want at least 2 metres separation between users of the different phases.

240V single phase is dangerous enough.

Three phase 415V is decidedly lethal.


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## cater_racer (May 1, 2005)

Thanks Chaps, I think I'll do what my neighbour did, and take each phase off into a seperate blue 16A socket. That way next time I can be generous to my neighbours.


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## clodhopper2006 (Aug 13, 2006)

err, but what about the lack of the neutral? Let me just point out that if you are using the earth as a return, then if you get a fault on the neutral side of an appliance then the appliance may kill you.


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## teemyob (Nov 22, 2005)

*Plug*

Our plug has a neat trick. If you have reverse polarity, it unscrews and you unlclip the Positive and Negative and swap them over.

No tools required.

Not seen them anywhere to buy mind!


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## cater_racer (May 1, 2005)

The risks are similar to any two pin connected enviroment, most devices these days in fact. The earth serves to provide a shield for metal chassis items but is largely redundant in many devices. Looking around me at the moment nearly everything has one of the two wire leads on it.


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## clodhopper2006 (Aug 13, 2006)

Look I'm trying to help you. I'm a chartered electrical engineer with 35 years electrical experience. Now i'm not being funny but your comment earlier regarding star and your comment regarding earth indicates your lack of knowlege about what you're talking about. 
So if you want to ignore good advice then you go ahead. I'll comment no futher on this thread.


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## safariboy (May 1, 2005)

Remember that you can get 400V or more between the two phases. I have only seen these leads once at a caravan club race course site. but share clodhopper's concern. 
You will certainly have at least one earthed appliance - your van. A kettle and toaster will also be earthed.


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## cater_racer (May 1, 2005)

Sorry Clodhopper I don't mean to be offhand, but seeing as you mention it I'm also a fully qualified electronics engineer, and I'm only pointing out that most devices these days only carry live and neutral beyond the plug.


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## clodhopper2006 (Aug 13, 2006)

cater_racer said:


> Sorry Clodhopper I don't mean to be offhand, but seeing as you mention it I'm also a fully qualified electronics engineer, and I'm only pointing out that most devices these days only carry live and neutral beyond the plug.


I said I wouldn't comment again but this is completely against BS7671 which describe a number of accepted eathing systems. It also insists that all socket outlets that are likely to be used outside are RCD protected. 
If you do this you will be removing your earth from you supply not just your appliance. 
You could make your van chassis live or any metal appliance or fitting if you go down this road.


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## TR5 (Jun 6, 2007)

I would guess that, if this plug is 3 phase and earth, then it is probably intended to be used for either 3 phase heating, or driving three phase motors.
Bear in mind that at 50 cycles p.s, each phase is at 0 volts 50 times per second, so becomes neutral, and the other two phases make up the 400 - 440 volts. This satisfies the neutral required for three phase elements or motors, but not for single phase general use, as there is no constant neutral.

Another concern would be that, if you devised this splitter with the three outlets as suggested, and if someone plugged into one of these and you into another, if one supply was crossed for any reason and their live went to your earth, you could end up having two live supplies into the other connection, effectively making your chassis and anything metal, live.

Touch this and/or your incoming supply and you have 440 volts through you, and no earth - ouch!!!

I am not a qualified electrican and don't profess to be, but have some understanding of 3 phase electrics, and would not advocate this set-up as being suitable for a normal 1phase supply.
3 phase should be suitably split to single phase outlets, with a permanent neutral and earth.

_"I'm only pointing out that most devices these days only carry live and neutral beyond the plug". 
_
Precisely my point, if another persons earth becomes your live (to neutral) you have two phases, no neutral, no earth!!

Clodhopper, I'm totally with you on this one!


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## gromett (May 9, 2005)

TR5 said:


> Bear in mind that at 50 cycles p.s, each phase is at 0 volts 50 times per second, so becomes neutral, and the other two phases make up the 400 - 440 volts.


Pedant time? erm at 50Hz surely it hits zero volts 100 times per second? once at the start of the cycle and once on its way to negative in each cycle?

In a three phase system I would not use neutral as earth personally.
Any way not getting involved in this one.

Karl


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