chrisb271

I put this panel up today,its mounted at a recycling plant i do a lot of work for.

The main cable in is 300mm ( USA = 600kcmil )


Attachment 298

Andy in ATL

The colors ain't right. Just kidding.


Thanks Chris, that's cool.

JohnJ0906

Neat!

That sure doesn't look like 600s, I guess it's the perspective of the camera.

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John from Baltimore
"One day at a Time"
All responses based on the '08 NEC
It's not my fault, it's not my problem, I'm not your solution.

beartard

A few comments, questions;

It looks like that panel was designed with the safety of the electrician in mind. The bus exposure is minimal and the manufacturer seems to have taken the trouble to make sure there's plenty of isolation between the spaces for breakers.

The main breaker switches the neutral (blue/common) as well?

Standard three-phase colors are brown, black, and grey? Interesting question (since Andy brought it up): are there really any mandatory phase colors in the US? As far as I remember, the code only specifies colors for grounding conductors, grounded conductors, and "high legs."

It looks like there's colored jacketing added to the feed conductors. Am I wrong? I don't think I've ever seen wire that big with a jacket color other than black. I have to admit that this approach looks a lot better than a ring of phasing tape below the lugs.

What is the phase-to-phase and phase-to-neutral voltage in the UK?

One more and I'll stop. I've heard of UK "ring" circuits. How exactly does that work and what's the purpose?

Sorry, but this is fascinating to me.

frenchelectrican

note that the bold is my reply in case you wondering

Merci, Marc

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Pas de problème,il marche n'est-ce pas?"(No problem, it works doesn't it?)

chrisb271

Beartard

Marc has given most of the details - thanks marc

The panel has most of its covers off to allow me to connect the wires to it,when all is replaced you can hardly see any copper other than the earth bars.

The UK ground wire has to be coloured (colored) green and yellow.
The phase colours are now what they call harmonised ( bit of a joke really as most EU countries will not accept them )

We use a Ring main for most house wiring instead of radial circuits.

We start off with a wire from the mains usually a 14 Awg then go to the first socket ( recepticle ) then from there to the next socket then the next socket etc etc and finally end up back at the distribution panel,so its a complete ring of cable we then feed it with a 32amp mcb.

All fed from an RCD ( GCFI )


Regards


Chris

beartard

Thanks for the answers!

So it seems that the ring circuit allows you to use a smaller gauge wire than would be necessary otherwise. Are the breakers designed to accept the "return" wire as well?

LawnGuyLandSparky

This is, conceptually brilliant. When you think about it, there's little more copper being used (just a return to complete the ring) and it effectively doubles the capacity of the circuit. Further, operating at twice the voltage, you realize a 400% increase in available Kw over an American 15a circuit.

frank

Just in case Chris doesn't mention it. If you sub fuse each appliance connected to an outlet on the ring. Then protect the ring cable with an mcb to suit the maximum working current. You can safely have as many appliances as you wish on the circuit' Although traditionally protected via 32amp mcb - you can make the ring cable as big as you want applying all the rules of safety/ diversity etc as you go. A great system. But would you believe that there is talk about not installing rings in the future. Someone somewhere commented on 'magnetic influences being generated by rings'. I get more magnetic influence from the TV than any amount of time sat next to a socket. But then. I'm just dumb.

Frank

frank

Chris.

What panel is that? It has the look of an MEM but can't really tell. I always go for MEM. Just loyal I suppose. The Merlin Geran have the safety MCB safety slide switch but these have caused me too many problems in the past. I make off the Board. Fit the lid. Switch on the MCB. The have to take it off again because I forgot to slide the switch. Or worse still. I am miles away when I get the call ' that circuit you just installed. Doesn't work!!!!!!!!!!!

Frank

Andy in ATL

Did you get that Beartard? I'm not quite sure why you have to complete the ring. I understand that you are at 240V. Why the ring.

beartard

I think I got it, Andy. By causing the end of the line to return to the panel, you can use smaller wire for the same amperage, possibly even saving on copper. But each appliance on the circuit is fused at the plug (accounting for the gargantuan plugs in the UK, no doubt.) So they can get a lot more capacity on a single circuit than if it were installed radially.

It does seem, though, that you have to take greater pains in doing load calculations before the initial install. How easy is it to predict exactly what's going to be plugged in on that circuit later on down the road? If you have a bunch of appliances fused at 5-13A on a 32A breaker, unless the duty cycle is intermittent, there could be "loads" of trouble...but then, that's really no different here.

Andy in ATL

I still ain't getting it. 240V, 14AWG , 32A= 120V, 14AWG, 16A


They are only getting 1A more on a "typical circuit...The voltage is doubled. How does bringing the wire back to the panel make the Ampacity go up. I ain't saying it don't...I'm just can't wrap my head around it. Does the resistance magically drop?

LawnGuyLandSparky

Electricity follows the path of least resistance, but it also takes all paths available to it.

A 14 awg @ 240v is still only 15a. Not 32a.

To understand the concept of a ring circuit, I'll "Americanize" it...

If you ran a 14awg from the breaker to a receptacle, and then daisy-chained to 10 more receptacles, you could load a maximum of 15a on that circuit. Now picture running the circuit back to the breaker after the last receptacle, and using a 30a breaker instead. That is the U.S. equivalant. Now you could introduce a 30a load anywhere in the circuit and still not overload a 14awg wire.

To add another dimension of cost savings, make that a 220v circuit instead of a 120v circuit, and replace every piece of utilization equipment with a 220v version. A 100w lamp @ 220v uses 1/2 the amperes as a 100w lamp @ 120v.

Where a U.S. coffeepot might be 1000 watts at 120v, the same coffeepot in the UK would only be 500 watts @ 240v to achieve the same performance. Therefore, not only does a ring circuit effectively double the amount of load a particular guage wire can handle (while using a little more wire) their 240v system ALSO allows for 2x as much power, while using the same guage wire.

te12co2w

I'm with Andy, I still don't get it. Could someone pretend I a beginner and walk me through this. How do you get 32a on a #14 wire?

LawnGuyLandSparky

You don't, you get 32a off 2 #14 wires - because the circuit is not radial, it's a ring. The hot starts and finishes on the 30a breaker. The neutral starts and finishes on the neutral bar.

Assume a 15a load on the 1st outlet. You'll "pull" about 15a on the hot and return the same. If you added another 15a load on the 2nd outlet, power would come off the breaker from the other direction along the ring, and return the same way.

Think parallel conductors...



Or go here:

http://www.answers.com/topic/ring-ci...cat=technology

beartard

A little research on UK plugs shows that they were designed with safety in mind as well. The prongs are insulated so that fingers and objects can't come into contact with metal even if pulled out of the socket part-way. Some outlets even have shutters that won't open til the ground prong "makes."

Another interesting thing is the cord can only come out the *bottom* of the plug (not the back, as is common in the US.) I have to ask: how painful is stepping on one of those things in sock-feet in the middle of the night?

frank

Not painful at all. You keep the plug head in the socket at all times.



Frank

chrisb271

Frank

Its a Hager board,it was a rush job and was the only one i could get at short notice.
You know the sort Frank,the machine is here at 2pm and we want to get working it at 2:15

I use mainly MEM gear as a rule but swap between that and smiths.

I have the same problem with merlin gerin,i'm usually just pulling onto the drive when i get that call to say it doesn't work and i think to myself,i could tell you why but its a little embarrassing

Chris