TT System issues
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- Опубліковано 2 жов 2017
- I was asked to carry out a condition report on a community center and initially thought it would be a great opportunity to capture some inspection and testing evidence for the 2391-52 Outcome 5 vid.
Unfortunately the installation wasn't suitable as the issues would change the approach as required in the 2391.
Wish I worked alongside a spark like you who actually KNOWS what he is doing! LOL.
Keep it up pal...👍
Some really helpful vids thanks for making the effort
That's bloody amazing
In Australia - we would have bounced the service, tagged it, and left. They would need to bring up to 2018 code, which means all of that crap is removed, and only a main switch, and RCBOs are installed. A bond to the earth mass would be required with low i. AS3000 does allow for alternative earthing methods (5.8) such as bonding to a steel building structure (as the buildings structure is buried into the ground) or the building rebar buried into the concrete - but as a utility, we'd never be satisfied if you mess with the principles of MEN.
Great vids as always.
Could you do one on testing and measuring Ra and how it's done and recorded
Crikey tis a thing of beauty Mr Ninja 😉
Soon you will be looking for AFDD’s and possibly Earth electrodes on every property,that installation looks like a school,glad you did an inspection when you did,hope you installed the correct equipment in the correct way,with the correct ppe with the correct paperwork and on and on and as long as we do our jobs correctly there is no problem,any one can pull other people’s work to pieces but it is a fine line between what is wrong and right,and sure enough this is wrong but don’t go over the top!they have already done that at the top,Jib,iee nic/eic money making
Not sure about AFDD's (at over £100 a piece) but here in the UK we have one of the best Earth systems on the planet! The exceptions are usually overhead fed (like this) and old! All new supplies need to have an Earth incorporated in them, and for that earth to be maintained in good condition by the REC! This is not the case for site supplies which are a special circumstance where we remove the system earth deliberately and the contractor needs to install earth rods and RCD's
Why would you be looking for AFDs and earth electrodes on every job?
AFDs are only suggested in 18th edition.
And anyway, this is condition reporting, 18th edition has nothing to do with it.
nice ending!! suspect the incoming had to go !!
It would be interesting to see what you recommended to sort out the discrimination/selectivity issue. 100ma RCD in place of the "main rcd" and send the FDB unit back for a refund? 😁
Living in Thailand no buildings are ever supplied with earth, none of the servicees are metal pipes.
Being dry an earth electrode Ze test is greater than 100 ohms.
Bonding to re-bar in structural concrete works best.
Would like to change systems from TT to TN-C however not allowed and dangerious to do so inside end users building.
In the US in the NEC, there is a special case allowed for an ungrounded electrical system (2 pole, hot/neutral, no earth ground) having grounded three conductor outlets (hot/neutral/earth ground), but it must be downstream from a GFCI recepticle. Maybe this is the case in this install as well? Could the main RCD be acting as a whole building Ground fault Interruptor?
IN our UK electrical supplies only the supply company can combine the earth and neutral .This is done inside the cutout and provides the main Earth . The supply company won't provide an earth on an overhead supply it must be created by the electrician . This is called a TT earthing system . The main RCD is providing protection for the whole installation however it does not comply with regulations for division of circuits . I hope you can make sense of this .
Ring UK Powernetworks and get them to PME the system 0.33 is high but below 0.35
How did this get passed !!!!!!!!!!!!!!!!!!!!!!!!
When you say you could not consider the Water Service as providing an earth to the building due to it having a plastic insert. Surely if it was a metallic pipe it could only be considered as a main earth if the building occupier owned that service and was in control of its condition i.e a privately owned water main?
The conduit that’s the incoming concentric service came in via would also need to be earthed as it could be considered as an extraneous conductor.
I enjoy your videos, sadly most of the poor workmanship you highlight I see on a day to day basis as an inspector myself. Keep up the good work
why is there so much overcurrent protection in series?
why no conduit for the cables?
got a 125 amp commando socket on a pme, they have a fly up to a marquee the total run is 100m or so my commando socket is about half way. a guy got a whack off a metal case of some stage equipment. I'm thinking its difference in potential i'm thinking of ditching the PME at the commando and TT with 100ma time delayed rcd at the commado socket does that sound right scratching my head ha
I think 30 Ma at commando socket it's outside and where the risk is. 100 ma too high.
I need to work with someone like you before im real old.
i can barely hold 2 leads, let alone 2 and a phone :)
A simple fix. Put a few earth rods in and change the first rcd
The box the CPC's are bolted to should be full of clay... 🙄😬
Shouldn't there be an earth connection coming out of the supply head? I beleive it is tied in to the N conductor. I know our house certainly does.
nope, this supply is tt so no distributors earth provided
@@conorlanders8401 It's using the same TN-C-S type cutout that we have, so he should have been able to reconnect it.
@@davepusey Only the DNO can do that and as its overhead fed they won't switch it to TNC-S because of the possibility you lose the neutral
@@steverobinson8170 here in South Africa everything is TNC-S these days even from overhead feed. Ground is too dry for anything else.
You know your stuff but why do you put the live probe on first then blue/neutral probe for rcd test
Blue/green probe first then live probe then live probe of then blue green probe of so u you have no live probe exposed👍🏻👍🏻
Because I'm doing it kack-handed with one hand.
The supply into the place was single phase right? Yet parts of it looked like it was meant for 3 phase how is that please?
The Earth Fault Protection unit is supplied for use with Three Phase systems; in this case, the single phase supply is connected to the 'red' phase input of the unit (the blue and yellow inputs are not connected) and the single phase output is collected from the "red" output terminal. The RCD is only measuring the difference in current between the three line conductors and the neutral; with all the supply current passing through the 'red' conductor and returning via neutral, there is no difference (unless an earth fault occurs), so the RCD functions correctly.
They've probably just linked the phases across in the bottom of the main switch in the secondary board so L1 supplies l2 and l3 into the breakers there's not actually 3phase their just used an old 3phase board is my guess
You do not know the meaning of dreadful workmanship.
UK sparky working in Thailand, living through electrical zombie apocalypse.
"This inspection is a shithole" 😂😂😂😂
Crap install that...
these cowboy electricians lol
Max Zs reading with 30mamp rcd protection is 1667ohms 🤔
Max Ze for TT system 200ohms 🤔
That's probably why that RCD was installed in an apparently silly place?
What exactly are you failing it on?
I'm sure someone will correct me if I'm wrong.
The first rcd will trip at the same time as the ones in the dB. So all circuit will trip at the same time,instead of just the one faulty circuit.
The main switch rcd after the tails should be a time delay. The others in the dB will be lower
@@nevermind824 Yea I know, that's irrelevant in terms of safety. I was wandering why he was going to fail the EICR.
Because there is no main earth
@@nevermind824 it's a tt system, using the gas pipe as the earth electrode, the ze reading was acceptable.
@@londontrada You can't use the gas pipe. It's illegal. reg 542.2.6 "A metallic pipe for gases or flammable liquids shall not be used as an earth electrode. Other metallic water suplly pipework shall not be used".
You can use the foundations as a electrode though if the reading is good enough
why does most English electrical work look like shit and dangerous??
🤗
32079rme
Have you never seen an overhead service with SE cable strapped to the outside of a building going into the top of a meter socket, then out of the bottom of the meter socket into the building to a panel in the basement?
Sadly very common no physical protection, no over current protection, no ground fault protection, but very fast and cheap to install!