Spot The Mistake

[telectrix]

As title. No prizes for the first correct answer.

 

[malcolmsanford]

yep, similar but not as ancient. i think that around the early 70's heads were supplied with the block attached in readiness for PME, but no link across to the neutral in the head. the way to be certain is to measure the pssc and pefc. if the readings are identical, then its TNC-S. if the pefc is lower than the pssc, then it's TN-S.

I don't like the tone of your inference there young man

 

[telectrix]

LOL. as i,m older than you malcolm, it's obvious that i was referring to the service head. a pot never calls the kettle black. one thing was a bit of a head scratch was the main bonding. gas meter was below the CU board and done in 6mm green, but then there are 2 imperial equiv' of 10mm going up and over. 1 is to water, but couldn't find the end of the other 1. using wander lead, the water main bond read 0.03ohms, so well in.

 

[malcolmsanford]

As it looks like a TN-S supply why would the main earth conductor be automatically to small?

Still would change it on a CU change to a G/Y.

Now we cleared up the TN-S factor as I asked why do people automatically assume that 16mm is the way to go for a main earthing conductor

 

[grimysparks80]

That one looks like a 6mm to me. id stick at least a 10mm in just as standard practice, depending on the requirements of course

 

[telectrix]

it's all 10mm now grimy, ( the water main bonding is original imperial, as near to 10mm as damn it. think it's around 8mm. )

 

[grimysparks80]

i had to do the bonding in 16mm the other day. had run out of 10mm and the company computers were down so they couldnt authorize an order for me. Hope they never change the size to 16 as it was a bugger to run in.

 

[Sparky Ninja]

Here's a classic I found a couple of years ago, there's 1 big balls up in particular.

View attachment 6957View attachment 6958

 

[johnboy6083]

I suppose malc, that it's just ignorance that we assume it's too small. Is it fully acceptable to size the main earth by adiabatic? If si, why is it always banded about about the 16mm? Is it to simplify it?

 

[telectrix]

Here's a classic I found a couple of years ago, there's 1 big balls up in particular.

View attachment 6957View attachment 6958

neutrals?

 

[Amp David]

Did you get it all done yesterday or did you pop back and finish up this morning tel?

 

[Silly Sausage]

Here's a classic I found a couple of years ago, there's 1 big balls up in particular.

View attachment 6957View attachment 6958

Is it the Line supply to the top RCD comes off the supply side of the isolator?

 

[telectrix]

managed to finish around 6.30pm. not 100% happy with a couple of the cables in the CU. going to re-dress monday, but had to extend some and couldn't leave without power for obvious reasons. also lost an hour going out for an RCBO and fixing a couple of faults, so was a bit pushed for time. guy wants me to do a bit of outside lighting for him, so will do at same time.

 

[Sparky Ninja]

neutrals?

what about the neutrals?

 

[truckster]

Bottom switch fed from top of top switch but bottom neutral fed from top neutral bar so bottom circuits would appear dead when top switch opened but still be live?

 

[malcolmsanford]

Is that blue neutral on the left hand of the board going straight to the neutral bar the supply neutral in, if so it's bypassed the main switch.