Crabtree C50's... What code, if any?

[MDJ]

They have loads of C50 boards on the underground.We call them widowmakers i hate the things.All testing on the underground is usually done on live boards as you cant turn off a board if it is feeding safety critical circuits such as cctv,fire alarms etc.Trying to get a neutral out of the back row when the board is live is not something i enjoy to put it mildly!

They are all being phased out as they are not being made anymore so it is hard to get spares and about time too

If you have spares I will be interested in them fella

 

[somersetsparks]

I believe they are the some as federal electric

 

[Essexboy7]

If you have spares I will be interested in them fella

Ok mate if i pick any up on my travels i will be in touch

 

[Engineer54]

I believe they are the same as federal electric

I think you could be right, the same Yank based crap!! lol!!



MDJ...

I haven't a clue why you like these breakers and boards MDJ!!
If you ever get the chance, test one or two on a primary injection (MCCB) test kit, and you'll see what i mean about the time/current curves of these naff breakers!! lol!!

 

[MDJ]

MDJ...

I haven't a clue why you like these breakers and boards MDJ!!
If you ever get the chance, test one or two on a primary injection (MCCB) test kit, and you'll see what i mean about the time/current curves of these naff breakers!! lol!!

I have several sites which I maintain for the council and there are litrally dozens of crabtree c50 boards on the sites, we are always changing things about, adding things, removing things etc etc and the council won't pay tens of thousands of pounds to have them all changed as there is nothing actually wrong with them, that's why I carry a few on the van and am always on the look out for any going cheap Fella.

 

[chilliwilly]

If were talking about those older black Bakelite MCB's, they were total crap when they were new, let alone now after 30 years service, boards were crap too!! lol!! Those things were of an ancient Yank design, with hit and miss Time/Current curves!!

Yes I know what you mean they do resemble the Cutler Hammer and Square D mcbs, to be honest the only time I had a problem with them was if the abience and or humidity were exeeded causing grease to run out of the linkages. Causing corrosion making them sluggish and stiff to operate in the case of o/l, or the fact with innaccessible terminals neutral bar.

When were bored working nights we had a test rig with the usual get up with various analogue meters set up for various kit, and we use to test the trip curve characterisitics of various o/l protection new, old, and spare, and their curves were in spec unless corroded.

 

[Engineer54]

The older Yank Bakelite MCB's from ANY of the American manufactures were crap, worst of all, the stab-in variety!! I wouldn't give a thank-you for any of them...
I don't have much time for many of their MCCB's either, especially those with the plug-in current modules, Jesus the times i've seen those things burnt and welded in, rendering the whole unit to be replaced!! lol!!

How did you test the time/current curve characteristics of those MCB breakers then??

 

[chilliwilly]

Connected them into the test rig, and started overloading their rating with resistive loads manually selected at 2% increments, and timed it using a bench made shotky ttl switched KC shifter that oscilated at 5000hz, if I remember correctly? In turn fed from the load side of the mcb that energised an em counter with reels about 2"/50mm circumferance calibrated in 0.01-100000 seconds that stopped when the mcb tripped. In the case of a short circuit, the same resistors were used but selected downwards, and the load live tails terminated onto porcelain insulators and dropped into a bucket of water.

The analogue meters were a combination of AVO and GE volt meters, ammeters, with a latching option. We would then note the time tripped and size of load applied, then compare the curve to the manufacturers, and the 15th edition trip curves. The ones that were in a dry environment were spot on, but the ones changed out from a damp or humid environment would be beyond the curves.

Eventually they got a spool fed recording ammeter which you could turn your back on but took the fun out of monitoring.

 

[Clive P]

Hi,

Many years ago I was told by an Electrical Engineer that when C50's Suffered a short circuit or overload they were no longer fit for purpose ( I'm assuming the time/current characteristics were destroyed ), so I always changed them out on a fault. I have no information to back this up, but because of that reason I've always been wary of them.

Regards.

 

[chilliwilly]

We did perform o/l tests afterwards, and they were ok providing that their rated short circuit capacity were not exceeded. At the time when they were made, I don't think they had the other rating that 60898 introduced with the reccommended s/c rating, and the other one that won't guarantee its service rating if exceeded.

At the end of the day, I would still rate them over other makes that are around now, such as proteus and the like. I wish I had access to the rig now to put them through their paces, and prove to C.all E.ddies F.irst that they are indeed the worse you can buy!

 

[Engineer54]

Well all the American units that we have tested in the past, on an MCCB test kit gave an equivalent in excess of the old Type 4!!! Some had an instantaneous beyond that capable of the test kit!! lol!! They are Crap, pure and simple!!

 

[Dcf]

They have loads of C50 boards on the underground.We call them widowmakers i hate the things.All testing on the underground is usually done on live boards as you cant turn off a board if it is feeding safety critical circuits such as cctv,fire alarms etc.Trying to get a neutral out of the back row when the board is live is not something i enjoy to put it mildly!

They are all being phased out as they are not being made anymore so it is hard to get spares and about time too

I too used to work in a big installation tha had loads of them fitted and also couldn't knock them off easily.
jesus there is some amount of live parts in one of they boards especially if the are chock ful of cables and trying to pull something new in..ooof let's be careful out there! Absolute junk in my eyes even dorman smith was better and that was saying something

 

[MDJ]

I too used to work in a big installation tha had loads of them fitted and also couldn't knock them off easily.
jesus there is some amount of live parts in one of they boards especially if the are chock ful of cables and trying to pull something new in..ooof let's be careful out there! Absolute junk in my eyes even dorman smith was better and that was saying something

Yes quite right I have to agree, they are difficult to work on if live, and lets be honest although a board should be switched off and dead before any work to it carried out I'm sure you like me and most of us know that in reality it isn't very often the case, however I disagree about the junk bit, and to add I like the fact they do come in 7.5 amps as well, they fit well in the boards and very easily removable, the down side is the silly clamps for the cables, very difficult to connect, thats the main weekness, tin hat on E54 will be here soon hehe.

 

[onions1066]

If you have spares I will be interested in them fella

Do you really want spares? What do you want?

 

[MDJ]

Do you really want spares? What do you want?

did you read my earlier post buddy?, I maintain several sites which has dozens of C50 boards and keep a small amount on the van, however if there are any going cheap I would be interested, now last thing, just because e54 who is someone I respect of course has a problem with them doesn't mean you need to jump on the band wagon, yes!!!!!!!!!!!!!!!!!!!! I would have spares if the price is right, is that okay ???