mbrooke
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I saw links where you could purchase the standard, but perhaps its being taken out of the 2017 NEC?
'Proof' that AFCI devices really locate arcs.
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I saw links where you could purchase the standard, but perhaps its being taken out of the 2017 NEC?
Boy, you sure got my curiosity up so I just got done rrmoing the side of both the 20a 1p Q and a C-H.
I'll see if I can get a digital picture of both in the near future.
But, both are essentially the same I that both have tyher bimetalic mag strip in the current path that deflects to release the latch. Both bimetalic strips pass through a U-shaped chanel located close to a flat piece of metal of the same length.
With the C-H breaker it is the magnitude of current of current passing through the bimag element that magnetized the U-shaped chanel that when the magnetic pull is great enough it pulls together with the flat piece to release the latch.
However, with the QO the current path through the U-chanel is made by looping the flexible copper stranded conductor directly under the chanel and then loops back around over the side of the U-chanel back to the end bimetalic strip. In doing so both the flexable stranded conductor as well as the bimage strip are in parallel with one another which would essentially double the magnetic field that magnetized that U-chanel..
In my opinion the QO breaker appears to be that the actual msnufacturing cost I would think to be greated than the C-H.
I also found that the means SqD uses to magnetize that U-chanel is interesting but the mag element in the C-H is I would estimate to be about 50% greasted in length though
Both breakers do have a thermal calibration screw located at the load end connection of the breaker which is cover be as label with the intent of making it tamper resistant.
I also have a BR which I want to disect and wonder if it is anything like the old Westinghouse quicklag C.
Now I have to clean my mess up.
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mbrooke
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Post pics, sounds like fun! 
Post pics, sounds like fun!
As long as had the big mess I just took my BR apart and boy is it cheep. Has the same TM structure as the C-H but is more chinsy. I does have a cute little arc chute though. EATON must make a bundle on it. $$$$profit.
In removing the side though I can't get the breaker to latch and close now so I can't close and trip the breaker. The portion that I removed must have kept part of the mech suppprted and in line.
I is somewhat similar to the old QuicklagC and arc chute appear to be exactly an some other parts similar. The TM structures are very similar. I jusdt notice why I can't get the BR to latch and close. My cleasr moderl of the QuicklagC showed that U cut off part of the mec h on my BR when I cut open the side with my dremel tool. Oh well.
Now I'll clean up.
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Tony S
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Only in your dreams, not in the real world.
Yes, you are right.
And now problem could be with any one of the six to twelve circuits and the utilization equipment they supply.
Lets say the its the defrost circuit on the basement fridge. It only happens sometimes when the unit goes into defrost. How does the electrician narrow this down in one stop? The clock $ starts running as soon as I am heading to the call.
This is the problem with using a single sensitive device on multiple pieces of a equipment.
It is a real problem, not an imagined one. It is the same problem electricians and home owners have with AFCI troubleshooting and you want to compound this by tying more equipment to one device.
That is not a step forward, that is a step in reverse.
Do you actually know anything about:
BS7671 IET recommendations for electrical installations
BS-EN61008 RCD’s
BS-EN60989 RCD’s
BS-EN61009 RCBO’s
If you did you may reconsider your comment.
BS7671 in revised forms is used worldwide as a recognised standard.
mbrooke
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Not only that, my understanding is that BS7671 is based on IEC60364, which is the foundation of every single electrical code on earth outside the US, Canada and Japan.
Tony S
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mbrooke
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Post pics, sounds like fun!
Damn!! The BR/Bryant is basically identical to the old Westinghouse QuicklagC. They are virtually the same. That gaes basck to about 1980, a 35 year old design. I had to remove the other side of my BR and I'll bet the parts are interchangeable. With both side off there is nothing to hold the parts together though.
With the QO ond C-H there is no need to remove both sides to view the function.
mbrooke
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peter d
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peter d
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I know very little about them but the greater point is that I don't need to know anything about them. We work under the NEC so knowing the British Standards is pretty pointless, wouldn't you think? There's no more need for me to know BS than there is for you to know the NEC.
peter d
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Not surprising since they were absorbed under the same corporate umbrella (Cutler Hammer) many years ago. If I'm not mistaken, almost the entire CutlerHammer/Eaton line is still based on original Westinghouse designs.
peter d
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:roll:
But you still put your 2 cents in.
BTW, arc fault logic and MGNs do have something in common, so nice try with the off topic claim
It is off topic. Utility arc fault logic has almost nothing in common with residential AFCI's, as you have pointed out many times.
peter d
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Let me give you a real world example. Let's say I have a sub-panel that serves pool equipment in an outbuilding or pool house (a very common situation.) Obviously, it's going to contain a lot of GFCI breakers to protect the filter motors, lighting and receptacles around the pool.
I have two choices - A) I can use individual GFCI breakers ($$$) or B) use one 2-pole GFCI breaker to protect the whole panel, and regular breakers for each circuit.
Option B is unacceptable. One fault in any branch circuit is going to dump the entire panel of pool equipment. This makes troubleshooting more difficult and unnecessarily costly.
But go ahead and advocate this style of branch circuit protection anyway. :happyno:
Tony S
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That we are
But isnt BS7671 based on the IEC60364?
In a way yes, but you have to consider how IEC60364 came about. It’s an amalgam of various codes and regulations developed by different countries over the years.
It may be the international electrotechnical commission international standard but it’s neither international or standard. If the regulating body in a particular country doesn’t like a part of it they just ignore it.
Does that sound familiar with the NEC?
mbrooke
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Both can learn from one another, both have their strong points and their weak points. Condemnation without investigation is said to be the highest form of ignorance. I choose to research everything before condemning it. Researching other codes has taught me a lot. For example I can wire a whole home with #14 without problems thanks to researching the CEC.
mbrooke
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Actually in this case I would go with option A because 5ma protection is required by code. All circuits combined would probably exceed 5ma of normal leakage current.
But I get your point, while cheaper on capitol cost it will be more expensive if a circuit fails.
mbrooke
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But its where it originated from (wave form analysis), and mostly because in an MGN system you cant set ground pick up values below a certain level: in laymen terms you cant use MV GFCI/GFP.
Utilities go with arc fault relays mostly when they cant use GFP. However in residential ground and neutral are separate so nothing is there to stop the use of GFP instead.
Tony S
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Peter,
Once you get used to correct testing methods fault finding is easy. Now we come full circle to testing and recording results.
Could someone give me a logical explanation why routine testing is such a taboo subject in the US?
Loop impedance and insulation testing will show any faulty connections or cables saving all those call backs to tripping AFCI’s. You can sleep easy in your bed knowing the house or whatever you’ve rewired will still be there in the morning.
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