ECN Forum Forums General Topics of the Trade Non-US Electrical Systems & Trades How long have you been using breakers

My Grandmother's house in suburbial Toronto was built in the early 1950s, and had (apparently original) breakers for the circuits, but had a fuse main and a flat rate fusebox for the water heater.

A point of note, her husband worked for an electrical supply house.

Some info about Diazed/Neozed.
http://www.ad.siemens.com/et/beta/html_76/products/sicherungss.htm

Siemens seems to only specify Diazed for higher voltage applications thesedays.

Neozed's a lot neater, safer (from a shock hazard point of view) and ideal for 230/400V stuff.

Those minized switch-fuses are common in Ireland on modern consumer units as a 63A isolator.


There is a large range of Diazed and Neozed fuses available. Maybe one of our Scandinavian or German electricians who has used the system more recently might know what the curves/characteristics are?

This Korean site shows you some of the Diazed family quite clearly:



[This message has been edited by djk (edited 06-08-2004).]

For domestic use (general purpose circuits and main fuses) I've only seen gL Diazed fuses, that means "full range conductor protection" and is claimed to be somewhere between the old fast and slow blow fuses. All I know is a 10A gL fuse acts noticeably slower than a 10A B breaker (ever tried to run a floor sander off a 10A circuit? With fuses the motor would try to start up, the lights would dim and then the fuse would blow. With breakers there was darkness almost immediately).

People only bought slow acting fuses for all uses, not only those which they were inteded to be used for. Do you see a parallell to the Americans overuse of 30 Amp edison fuses?

To get around this, the gL/gG fuse have replaced the slow fuses. If anyone asks, you tell them it is a slow fuse. The curve is supposed to be slow for moderate overcurrents (e.g. a starting motor) and fast for very high currents (a short circuit).

Trip curves and more can be found here: {In Swedish, English and some German }
http://www.ifoelectric.com/resource/diazed.pdf

The leading Swedish manufacturer of fuses have sold over 3 billion Diazed fuses to date!

[This message has been edited by C-H (edited 06-08-2004).]

Given the info so far it would appear that Max earth loop might be going to be less for any given circuit. So radial circuit lengths may need to have been considered more closely.
Cant for the life of me think why the curves did not appear in the Irish Codes if the fuses were / are so popular there.

They were and are still in the codes somewhere! They haven't been used, other than as a main-fuse protecting the entire consumer unit, since the early-mid 80s.

In general, where a new circuit is added to a neozed/diazed board the electrician will add a breaker. The boards use the same DIN rail system.

In many cases the fuses would have all been replaced.

Diazed fuses are no-longer permitted in new installations. This has nothing to do with the effectiveness of the fuses but rather more to do with a potential shock hazard when changing them. Modern Neozed and Minized fuse holders don't have this problem.

Neozed is permitted, but MCBs are recomended and have been the norm for quite some time.

Most installations from the mid-1970s onwards are MCB based and the standard siemens and hager MCB boards begin to appear around that time. However, Fuses, were still being installed by some electricians right up until the mid-80s.

Neozed fuses are STILL the norm as the main protective device on almost every consumer unit in Ireland and it's only in the last few years that we're seeing 63A / 80A main breakers appear.

Normal set up:

63/80/100A supply fuse (typically BS or IEC) sealed.

Meter (sealed)

Main isolating switch (power company provided [built into some recent meters]) connections to this switch are sealed by the contractor. It's designed to safely and completely isolate the system when it's being worked on and not for switching loads.

Consumer Unit:
Main switch (for isolation)
Main fuse (commonly 63A neozed) Main MCB has started to replace this little by little.

to 30mA RCD (where required i.e. not necessarily on cooker / lighting circuits (in older installations) )

to final circuit MCB (or Fuses in old installations)

Where MCBs are used 20A radials normally feed the sockets. (16A MCBs are sometimes used)
Where fuses are used 16A radials normally feed the sockets.

32A ring circuits are also used, but not quite to the same extent as in the UK.

(BS1363 sockets and fused plugs are the norm in any modern installation here (they begin to appear in the late 50s/early 60s). ( Schuko remained a permissable option, but was not widely available and was rarely used.) Round-pin BS546 was also used but disappeard as soon as BS1363 became available. The 5A version is still used in lighting applications. The 15A version was common place in theatre lighting but has been replaced in recent years by blue CeeForm industrial plugs (required by the health and safety at work legislation) )

Fixed appliences are almost always connected by means of a fused spur in both ring and radial systems.

Lighting is normally 6 or 10A depending on how it's configured and what the loading is.

Cooking can be 32-45A (UK style socket/cooker switch cooker control units are not permitted as the socket would have no RCD protection)

Instantanious showers are the same but ususally use an RCBO or a seperate RCD/MCB combination.

djk, thanks for that realy comprehensive drscription, I endorse the irish way of thinking with the socket on the cooker outlet. Am I right in thinking that you provide fusing ither side of he meter and then final circuit protection. Thats somthing thats seldom done in the UK other than perhaps TT system. Most times here its straight out of the meter into an isolator that integrated into the consumer unit.Then straight onto cpd's via common rail busbar.

yup, there's protection on both sides of the meter.

The power company provides it with a service fuse, which is very similar to the UK version.

The meter has an isolating switch on the bottom to allow any electrician working on the system to totally isolate it.

and then on the consumer unit we have another main fuse and isolating switch. Sometimes this is provided by a Minized switch/fuse unit.

Older installations wouldn't have the isolating switch on the meter but would still have fuse protection on both sides and a main isolator on the fuse board.
It's just the way it's always been done.

They've been VERY slow to allow anything other than a melting VDE specified (i.e. neozed) fuse as the main protection on the consumer unit. a Main MCB is a very new departure and is still rare.

DJK, Dont have a problem with that! sounds good to me after all when we get on to industrial installations we do it.We have a panel board or simular with Mccb incomer straight after the meter or even BS 88's. Yes I'm with the Irish on that one good on Ya.