Test Equipment Anonymous (TEA) group therapy thread

[AVGresponding]

Yeah a lot of those cheap ones use copper or brass coated steel for the spring contacts; sounds like they should be better but they heat up more and age faster because of the higher resistance.

Here's one for the knob twiddlers: https://www.ebay.co.uk/itm/Digitimer-NeuroLog-Systems-Test-Measurement-Unit/352997155418

And CDL have another of those 2.5 kV beasts: https://www.ebay.co.uk/itm/LKB-Bromma-2197-Bench-Top-Power-Supply/352997054311

[BU508A]

Just replaced two sockets in my place. One of the cheap shit ones that has been in there since I moved in wasn't smelling too good.  Cracked it open and it smells awful inside. Looks like plug contacts have been arcing which is shit as all it had was an XB one and a laptop plugged into it. Have put some MK ones in instead.

Are you talking about mains connectors?    What is a "XB" and what is a "MK"?

[med6753]

More re-caps.

Fluke 8050A before.



After.



Fluke 8010A before.



After.



Happy Campers. 



That takes care of the re-caps for the time being. This week's to do's: Get the compensation done on the Type 1A2 plug-in. I also need to replace the NVRAM battery in the 2430. As far as I know it's the original battery. If it goes dead you lose all the cal data which means you are screwed. And you also need to provide back up power while you change out the battery. Luckily the battery is still readily available from multiple sources. But getting to it will be somewhat of a pain because boards have to be removed to get to it. I should also consider re-capping it's SMS supply but that's even further buried deep inside sandwiched between several boards. 

[bd139]

Just replaced two sockets in my place. One of the cheap shit ones that has been in there since I moved in wasn't smelling too good.  Cracked it open and it smells awful inside. Looks like plug contacts have been arcing which is shit as all it had was an XB one and a laptop plugged into it. Have put some MK ones in instead.

Are you talking about mains connectors?    What is a "XB" and what is a "MK"?

Yes. Sockets.



XB is me being lazy. XBox

MK is manufacturer of UK electrical stuff like plugs, sockets etc. http://www.mkelectric.com/en-gb/Pages/default.aspx ... reasonable quality items. Think I paid £4 each for two of the sockets above from RS. Apparently still made here it said on the pack

[Cerebus]

Just replaced two sockets in my place. One of the cheap shit ones that has been in there since I moved in wasn't smelling too good.  Cracked it open and it smells awful inside. Looks like plug contacts have been arcing which is shit as all it had was an XB one and a laptop plugged into it. Have put some MK ones in instead.

Are you talking about mains connectors?    What is a "XB" and what is a "MK"?

"XB" - dunno.

"MK" - the commonest UK brand of reasonable quality electrical fittings. Plugs, sockets, switches, contactors, distribution boards etc. Acceptable quality but my old sparky friend swears by Crabtree - equal or better quality and better price.

[BU508A]

Ah, thanks for the explanations.
The corresponding brands here in Germany are Jung and Hager, I think.

https://www.jung.de/en/

https://www.hager.com/

[AVGresponding]

Hager stuff is nice. MK make a lot of their stuff in cheap far east sweatshops now, the quality has dropped a lot. BG are probably as good as MK nowadays.

Crabtree are good, I like Clipsal too, I think they are quite popular in Oz.

[bd139]

Yeah the MK socket blocks are a piece of shit. I buy the Brennenstuhl ones now. Seem to not be made of poo. I would have got some Crabtree ones in but that means hauling my arse down the road to Screwfix and I already had some RS crap on the way I was waiting in for. MK it was

[BU508A]

I know Brennenstuhl primarly for their multiple socket outlets like this (example):

[bd139]

That's the ones. I've got a much smaller one of them under my desk



Edit: interesting. White, economy version of the MSO5000:



Still £931  . TBH the DS1202Z and a shite logic analyser is probably a better buy. Edit 2: or a cracked arse end MSO5000 

[BU508A]

Which fuses do you use in the UK for the mains socket circuits? 10A? 13A? 16A? (1.5mm²)

Here in Germany it is usually 16A for 1.5mm² (however technically it should be 2.5mm² for 16A)

[BU508A]

That's the ones. I've got a much smaller one of them under my desk



Edit: interesting. White, economy version of the MSO5000:



Still £931  . TBH the DS1202Z and a shite logic analyser is probably a better buy. Edit 2: or a cracked arse end MSO5000 

The Brennenstuhl looks much nicer! 

[med6753]

What nightmares are made of.  To refresh my memory I pulled the 2430 parts mule out of the closet to look at the PSU. This is the supply AFTER pulling 3 boards above it. And I'm not sure how it comes out. Gonna have to RTFM. Hopefully there's guidance. And look at all the capacitors! Holy crap. 

And changing out the NVRAM battery is going to be no prize either. 2 boards are sandwiched together and they have to be separated to gain access to the solder side of the board to swap it out. 

[AVGresponding]

@med, I do like the look of the 8050, but I need to be strong and not buy any more bench meters until I have all my current ones properly mounted   

It looks similar in capability to the 8060, which as a handheld is small enough that I don't have to rearrange anything...   

I've been trying to find an 87 III for sensible money for a while also, and looking at scopemeters...   

@BU508A, the maximum allowable fuse in a UK BS1362 plugtop is 13A

[bd139]

Which fuses do you use in the UK for the mains socket circuits? 10A? 13A? 16A? (1.5mm²)

Here in Germany it is usually 16A for 1.5mm² (however technically it should be 2.5mm² for 16A)

It sort of works like this:

1. RCD / breaker on the ring main (may be multiple rings - we have 4) .... 30A total per ring. That's 2.5mm cable.
2. Each socket is specced to draw max 13A.
3. Socket block is usually fused to 13A or 10A depending on if it's good or shit quality.
4. Individual plugs are fused 3A, 5A, 13A usually.

[AVGresponding]

30A and not 32A?

We're starting to use 4mm^2 radial circuits a lot more (commercial premises) as it removes the possibility of a ring-within-a-ring, amongst other things.


EDIT: One thing I've noticed recently is undersized conductors (ie supplied as 2.5mm^2 but actually as small as 2.2mm^2). Guess the manufacturers are cutting as many corners as they can get away with...

[med6753]

You Brits and your ring circuits. Totally non-Kosher and would never fly here. 

[BU508A]

I never get used to this concept of the fuse in the plug. Is that really that helpful? 

[bd139]

30A and not 32A?

We're starting to use 4mm^2 radial circuits a lot more (commercial premises) as it removes the possibility of a ring-within-a-ring, amongst other things.

Not sure what current regs are. 4mm is what we have in the office AFAIK but that's wired as spurs and we have whole strings of xeon crates off it.

[bd139]

I never get used to this concept of the fuse in the plug. Is that really that helpful? 

Yes it protects the lead. So if the IEC lead or inlet goes short or faults it blows the fuse rather than gives you a nice smoky cremation off the cable

[AVGresponding]

I never get used to this concept of the fuse in the plug. Is that really that helpful? 

Possibly...

[med6753]

I never get used to this concept of the fuse in the plug. Is that really that helpful? 

Agreed, but I do like the idea of a switch in each outlet.

[Cerebus]

Edit: interesting. White, economy version of the MSO5000:

The white would be a welcome relief. Experience has now taught me that the black MSO5000s are hell to find a control on if it's one that has not yet become part of your 'muscle memory'.

That said, a couple of weeks with the scope and I'm liking it. The only time I'm less than fully chuffed is when using the horizontal position control (and to a lesser extent vertical position an trigger level controls), the laggardness makes you wonder whether you're turning the knob the right way. I'd quite like the features of this scope with a nice multi-tone grey HP scope appearance and instant UI response of the HP 546xxx era.

[BU508A]

I never get used to this concept of the fuse in the plug. Is that really that helpful? 

Yes it protects the lead. So if the IEC lead or inlet goes short or faults it blows the fuse rather than gives you a nice smoky cremation off the cable

And how do you distinguish between a cable with a 3A fuse and a 13A one? If you are going to use the wrong cable, then either it blows the fuse, or, the fuse doesn't really make sense imho.

[AVGresponding]

The use of rings as opposed to radials always seems to provoke robust discussion amongst sparkies   

I've seen rings with 4mm² due to length of run, but that's not really allowed now due to the effect on tripping time for the RCD/RCBO/GFCI.

It's not unusual for testing to reveal things the installation sparky doesn't want to see, such as overly high resistance or impedance, because the run is too long or the cable undersized.
You'd be disgusted and probably alarmed at the number of times the test results are "massaged" to prevent the need to redo the work properly.
Hell, I know of test sheets being shredded to cover up test fails on undersized SWA...

In every instance of this, the installation sparks told the line manager beforehand that the design was wrong, but were told to "do what the drawing says".

One of these days there'll be an "incident" and there will be head shaking and I-told-you-so's, and the people with their signatures on the paperwork (not me) will be in a LOT of trouble (except it will be fudged and those responsible will probably get promoted to where they can't do more damage).   

/rant


EDIT: @BU508A, the plugtop should have the fitted fuse size displayed on it. Moulded plugs also often have a window in the fuseholder that allows you to see the colour of the fuse.
This partially helps, as 13A are brown, 3A are red, but unfortunately, 1A, 2A, 5A, and 10A are all black...

Good grief, I think I edited this post half a dozen times