Consumer Unit problems

[carlyai]

I have a Schneider Easy Pact 100 A 25 KA outside load centre or Consumer Unit.
While looking for a phase not working problem (another thread), I poked around resulting in the phase returning with intermittent arcing under the knurled Allen screw. I tried to tighten the screw, but the female thread in the black bakelite CU must be stripped as the Allen screw will not tighten.
 
Question 1.
Do you know if I can just replace the black bakelite/plastic, or do I need to buy another CU?
 
While having a close look at the CU, I noticed that more than one Allen screw connection to the 60A breaker appears to have been arcing as well. I also noticed that the right hand, and middle black bakelite seems to have been melting.
The 3 phase breaker in the CU is 60A and has never tripped.
Question 2.
If the CU is 100A per phase unit, why does the bakelite appear to have melted on the middle and RHS Allen keys side? Is it because of the proximity to the bacelite high resistance joints created by the stripped Allen screws female threads?
 
If I have to replace the black bacelite, I can probably do it myself as the 60 A breaker will be left in circuit. If I need to buy a new CU I think it's a job for my electrician. He was the one who installed the CU in the first place.
 

 
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[Forkinhades]

Seems like a loose connection causing the arcing. If you can get the Allen screws out, then your good to go, if that's where the thread has gone.

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[Forkinhades]

Cables should also be crimped on. Pictures are unclear.

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[carlyai]

Seems like a loose connection causing the arcing. If you can get the Allen screws out, then your good to go, if that's where the thread has gone.

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So you think it's the male Allen key thread, not the part it screws into? Good thought, thanks, will take a look.

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[carlyai]

Cables should also be crimped on. Pictures are unclear.

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Better pics.
The Allen screws screw into a bus.


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[carlyai]

So you think it's the male Allen key thread, not the part it screws into? Good thought, thanks, will take a look.

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Having a better look, and the Allen screws do screw into a bus.

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[Forkinhades]

Ah I can see what you mean now. If the female thread has gone, then I fear that you are screwed. No pun intended.
I would try spring washer and a washer. Which should be standard on that piece of kit.

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[Forkinhades]

Another possibility is to tap a larger bolt on.

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[carlyai]

Ah I can see what you mean now. If the female thread has gone, then I fear that you are screwed. No pun intended.
I would try spring washer and a washer. Which should be standard on that piece of kit.

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Seems I'm screwed. It's the female part.

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[Forkinhades]

Looking at that, you can retap the thread, to next size up. Lots of bar to work with.

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[Forkinhades]

Get spring washers aswell. Any room at back to put a nut?, would need to get spanner in to hold it.

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[carlyai]

Another possibility is to tap a larger bolt on.

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I thought of that, not too sure if Global House etc have thread taps and a selection of Allen screws.
The best option I think.
Trouble is I can't take the Allen screw with me, so will have to try the Muan Thai Outlet in Roiet first, this is where I bought the CU.
I can nearly hear the reply...' we can sell you a new CU but don't have the Allen screws.'
I did notice a big flash from the HR joint when I reconnected everything and the house pump (300 W) and the aquifer pump (700 W ) both kicked in together. What would the start up current be, approx. 15A?
Seeing SWMBO is huffing and puffing at the moment, tomorrow might be a good time for a Roiet road trip.
There's a downside in living in Isaan without an Isaan house. Everytime there is an electrical issue, or pump or water or pool cleaning issue, and SWMBO gets wind of it she gets huffy with ' what am I going to do if you die? No one's going to be able to fix the place.'

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[Crossy]

Have a look for these self-drilling screws, not the regular self-tapper type, these have real threads. Take care on the length, things could get "interesting" if a too long screw touches something it shouldn't

 

[carlyai]

Seems I'm screwed. It's the female part.

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There is an excuse for a spring washer on the Allen screws. I put another spring and flat one on the RHS one, seemed to fix it, but I can't get the middle one out it just spins. It does have a lose and tight spot, so screwed it to the tight spot.
If I can't find a tap and correct Allen screw, I suppose I could get a bigger screw and cross thread it in. Nah, I couldn't do that...[emoji848]

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[carlyai]

Have a look for these self-drilling screws, not the regular self-tapper type, these have real threads. Take care on the length, things could get "interesting" if a too long screw touches something it shouldn't
 

Thanks, like thinking I think.

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[VocalNeal]

What size key are you using? Then you can determine what size screw you have. https://www.metricmcc.com/catalog/Ch1/1-32.pdf

 

The problem then becomes finding the next size up in imperial to get close. Or simply go up one size metric. Buy a tap set and... Looks like there is enough meat!

Edited February 17, 2018 by VocalNeal

[Forkinhades]

Can you not get a terminal driver on the middle one, and keep pressure on to lift it off as you turn?

 

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[carlyai]

Can you not get a terminal driver on the middle one, and keep pressure on to lift it off as you turn?
 
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I tried with a flat screwdriver lifting and some bullnose pliers pulling, but no go. Didn't try too hard as I need a connection until I fix it.

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[carlyai]

Another question while you're all bored and got nothing to do...
Crossy I notice that you installed large analogue meters for your Amps and Volts near your stabalisers. Look good. Any reason you didn't use the digital voltamps meters?

Also, I need to monitor the voltage and current on the 3 phases at my CU, but not sure how I'd do it with the CU I have. I don't wish to wire anything to the feed from the meter, I want to work on the other side of the 60A breaker with it off. Or would a different style CU, with the same dimensions be easier to wire up?


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[carlyai]

What size key are you using? Then you can determine what size screw you have. https://www.metricmcc.com/catalog/Ch1/1-32.pdf
 
The problem then becomes finding the next size up in imperial to get close. Or simply go up one size metric. Buy a tap set and... Looks like there is enough meat!

Thanks VocalNeal, big help, I'll check it out.

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[Crossy]

16 minutes ago, carlyai said:

Crossy I notice that you installed large analogue meters for your Amps and Volts near your stabalisers. Look good. Any reason you didn't use the digital voltamps meters?

Actually we now have multiple digital beasties too (read Volts, Amps, Watts and energy consumed), set up for incoming supply (along with the analog meters), AVR output and genset output.

 

Analog meters are great for "a quick glance to verify all is well" (this is why aircraft instruments are still analog look-alike, the pilot sees all the needles horizontal when all is well, anything off horizontal or bouncing around means trouble) they also react more quickly than digitals, handy if you have lights flickering.

 

 

Wifey doesn't moan (at least not verbally) just lets her crazy farang do what he wishes.

 

[carlyai]

Thanks VocalNeal, big help, I'll check it out.

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The key size is 4mm, this seems to correspond to the screw threaded part diameter size. So I'll try for a 5mm Allen screw or 5mm roofing screw.

Also a tap set. I suppose there are good and bad tap sets at Global House?

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[Crossy]

25 minutes ago, carlyai said:

Also a tap set. I suppose there are good and bad tap sets at Global House?

Even the cheap Chinese carp should be OK in your bus-bars, the "metal" isn't exactly tough even in the big-name stuff.

[carlyai]

Usual it is copper. A very "elastic" material to make thread. When you go for M5,  you should drill 4.2mm. (M6 5mm) But you can try without drilling. The easy available hand taps are marked. with one ring is the first one, with two rings is the second one, and without rings is the third one. The rings are usual placed on the end from the tap, close to the square. When you can find a machine tap, that is even better. They cut easier.
 
If available apply some WD40 or (better) engine oil on the tap.
 
Arjen.
 
 

Hi Arjen. Sorry I don't understand. Are you saying the taps are made of copper, or the material to tap into?
It's a long time since I was trainee/apprentice, but I thought the taps were made if steel. I also don't understand about the rings.

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[carlyai]

Thinking about installing the analogue voltage and current meters, I could probably install another metal CU box near the first one. Then take out the 3 links between the main breaker and the bus bars. Then run 3 cables from the out side of the main 60 A breaker to the new box and current meters and back to the bus bars. Take the volts meters of the corresponding Amp meter and other side to neutral.
Not much room.
Probably have to make the wires come up vertically from and to where I remove the links from the 60 A breaker to the buses.
Only other way may be to have individual digital current/voltage/energy meters in the house consumer unit, the garage/aquaponics/ pool pump CU and the back aquifer CU.
That would be 3 meters in the house CU and 1 each in the other CUs.
Probably be safer, as red ants tend to periodically invade the outside consumer unit.
Any thoughts?
@Crossy have you a reference for those digital volts/amps/energy meters?


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[Crossy]

36 minutes ago, carlyai said:

@Crossy have you a reference for those digital volts/amps/energy meters?

 

These are the ones in the photo https://www.aliexpress.com/item/Digital-LCD-Blue-backlight-AC80-260V-100A-volt-amp-meter-with-Transformer-coil-voltage-current-power/32340279544.html

 

 

Dead easy to install, just slip the current transformer onto the bus (hopefully it will fit) or incoming cable and hook the voltage sense to L and N. They do make a 3-phase version for a more compact installation.

 

EDIT Looking at your board I suspect you will be slipping the CTs on the incoming supply.

 

 

 

 

[carlyai]

 
These are the ones in the photo https://www.aliexpress.com/item/Digital-LCD-Blue-backlight-AC80-260V-100A-volt-amp-meter-with-Transformer-coil-voltage-current-power/32340279544.html
 

 
Dead easy to install, just slip the current transformer onto the bus (hopefully it will fit) or incoming cable and hook the voltage sense to L and N. They do make a 3-phase version for a more compact installation.
 
EDIT Looking at your board I suspect you will be slipping the CTs on the incoming supply.
 
 
 
 

Yes on the incoming cable into the 60 A breaker, seems the way. Didn't know it would be so easy.
I'll look up a 3 phase distribution board, see what they have on offer. Meters should be pre wired.

As another aside... looks like all the Allen type screws are arcing between the excuse for a spring washer and the busbars. I changed the back pumps to the LHS phase, blue, the one that didn't seem to be arcing, and when the back pumps kicked in it looked for a second that someone was arc welding around the spring washer. Fissing and poppying then silence. Must have welded a good connection as I couldn't get it to do it again.
Maybe that's a fault with those CUs?
I'll check out other units when I get to Roiet.
I'm obeying again, so all is OK. [emoji6]

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[Forkinhades]

They are good units. Normally come with spring washer + washer. Allen keys should be torqued up as well.

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[carlyai]

The material to tap into is from copper. It does not look red, as it is plated with Sn. Hand taps (the set what cmes in three pieces) are usual from HSS steel. Machine taps (only one needed) ar much harder then HSS.
 
The rings....
 
The lowest one has one ring, it is the first tap, the middle one has two rings, it is the second one. The one most on top has no rings, it is the last (third) one.
 
Hope this helps!
 
Arjen.
 
 

OK, thanks, got it.

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[xylophone]

Something you may wish to think about, if indeed it applies these days, and it may save you going through all of this trouble............ when bakelite or something like it's equivalent, overheats and has already had some arcing near it/around it, then it changes from being an insulator to a (part) conductor!!

Saw this many times and once this material became subject to arcing, it was always advisable to change it completely because overheating and further arcing, if not a complete burnout would occur.

Something to possibly consider?