Brown toggle Type 4
Orange toggle Type 3
Green toggle Type 2
White toggle Type 1 (Very rare)
Orange toggle Type 3
Green toggle Type 2
White toggle Type 1 (Very rare)
You need to refer to manufacturers data for max Zs values.
Impossible now as Federal Electric are no more. There are many internet Tables you can look at as per #6 but these can only be taken at face value. Merlin Gerin, Federal Electric, Square D and Dorman Smith were the most common producers and all quote variable maximum values of Zs so one Table does not cover all brands. Manufacturers Tables also quote 0.4sec and 5sec disconnection times. The attached fax came from Federal Electric many years ago, I have overwritten so it is legible.
Out of boredom this is from Dorman Smith.
Cant open it :-(
Thats brill thank you very much for taking the time to assist!
I must warn you that sheet is 25 odd years old but it is from the horses mouth.
In other words, good enough! You have helped a fellow Northamptonian out good man.
T
Toneyz
Don't forget that all the max Zs was adjusted in past editions of BS7671 for 230v and Cmin so values may have to be adjusted.
As I said those Tables are 25 plus years old.
Type 4 devices have trip characteristics of 50×In so you could calculate a maximum Zs value although this is likely to be much less than the manufacturers guidelines, this is because 50× is the worse case scenario due to standards allowing between 10 - 50 × In. It is possible on higher disconnection times the thermal trip is considered over the magnetic trip.
It’s worth bearing in mind that Federal Electric went under because they fraudulently falsified test results of their MCB’s. There never was a product recall because it was deemed too expensive and it was cheaper to settle any claims through the courts. So it might be prudent to get rid of the fire starters while you have the chance.
How would you word that on an eicr like the OP is doing.
They already don’t meet the maximum earth loop impedance allowed and under the 18th Edition will do so even less. He could also just note the safety implications in the recommendation section of the E.I.C.R. and let the client make up their own mind. It’s all about risk management. I personally have never seen a Federal Electric breaker burned out above 32A. They seem to fair better at higher ratings.
T
Toneyz
If that was true I would have thought they would have been forced to stop selling them and we would have had it all over the trade press.It’s worth bearing in mind that Federal Electric went under because they fraudulently falsified test results of their MCB’s. There never was a product recall because it was deemed too expensive and it was cheaper to settle any claims through the courts. So it might be prudent to get rid of the fire starters while you have the chance.
I don't understand they don't meet maximum efli values.
My apologies, poor wording on my part. In the opening post the OP stated that most of his circuits were over the max zs threshold on the type 4 breakers. I also don’t know why they are still for sale. Maybe they solved the problem with the breakers but the damage to their reputation was still done.
Not sure why he stated this as he had no idea what to compare the values to. But I agree they are nasty devices.
Well your values must have been well below those on the Federal sheet I posted.
T
Toneyz
Was there not the tables in the regs books in the 15th or before for max Zs for BS3871 circuit breakers?
No they have never been listed due to their variable characteristics.
Ind
Indeed they were!
T
Toneyz
Is that all BS3871 MCB's or just the Federal ones?
All BS3871 Type 4 devices. Type 1, 2 and 3 were always included until superseded by EN60898.
T
Toneyz
Thanks for enlightening me on that westward as I was thinking to myself there are tables that include max Zs for BS3871 devices but does not include type 4.
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