Tt System No Visible Earthing

[Jammin]

Hey guys need a bit of advise as a newly qualified spark. I've started installing solar pv systems in Northern Ireland and yesterday went to look at a potential job. Its a TT system with no visible Earth the main incoming supply is in one of the out buildings I looked everywhere nothing in any of the consumer units no bonding etc its very old! never come across this before, so I know I'll have to put an earth rod in but my question is, if I run a new cable from the inverter in one of the out buildings straight to a new garage board by the main meter bypassing all the existing wiring so just my installation Is earthed, and advise the customer to get remedial work done on all his existing wiring is that ok? or do I have to sort it so everything is up to regs in which case its not worth doing the job.

Sorry if I'm a bit thick but I'm new to all this so any advise would be much appreciated.

Thanks 

 

[steptoe]

First up,

Is the inverter you are installing compatible with TT? Not all are.

2nd, yes, you have to have all earthing and bonding up to scratch.

I could have a look at it on Saturday if you want, cheap rates,

 

[SPECIAL LOCATION]

Hey guys need a bit of advise as a newly qualified spark. I've started installing solar pv systems in Northern Ireland and yesterday went to look at a potential job. Its a TT system with no visible Earth the main incoming supply is in one of the out buildings I looked everywhere nothing in any of the consumer units no bonding etc its very old! never come across this before, so I know I'll have to put an earth rod in but my question is, if I run a new cable from the inverter in one of the out buildings straight to a new garage board by the main meter bypassing all the existing wiring so just my installation Is earthed, and advise the customer to get remedial work done on all his existing wiring is that ok? or do I have to sort it so everything is up to regs in which case its not worth doing the job.

Sorry if I'm a bit thick but I'm new to all this so any advise would be much appreciated.

Thanks 

Hmm..  'new to this'... 'never come across this before'...

I would doubt you have come across much at all before if you are new to this..?

and only done a short course...?

But whatever you have or haven't seen before,  I assume you have done some regs training...

AFAIK reg 132.16 still applies to all alterations to all installations be they CU's circuits, Solar, or whatever..

Invisible TT rod.......

It is not uncommon for an old installation to have an earth rod that has become hidden or buried over the course of time...

Did you take any earth loop readings to establish the condition of any earth even if you cannot physically find where it may or may not be terminated?

On the one hand you suggest telling the customer to get remedial work done...  (customer pays)...

so why not get the customer to pay you for the remedial works as well as for the solar???

Cant see why you say it wont be worth doing the job?? 

Just quote for ALL works that you consider need doing...

if they NEED doing...  Then someone should be paid for doing them...,   (why not you?)

Unless you wait for the customer to do some work himself..

then you just quote for the bits you want to do..

:C

.

 

[Jammin]

Hey Steptoe. Thanks for your reply its an sma sunnyboy tl inverter I assume there tt compatible no problems in the past. I thought I might have to do all the earthing but it's going to be a nightmare the consumer units look like jewellery boxes and the fuses look like there made out of porcelain, plus when I looked inside the CU because there is nowhere to terminate the earth most of the T+E cables terminated in there have had the earth cut back so far there's no way of extending them. Also no RCD in place anywhere.

Think this guy needs a full rewire in that case, as I can't think of another way around it. Don't think he wants to go down that route and my boss has already taken a deposit. Think I might have to bite the bullet on this one and tell him I can't do it.

Thanks for the offer of having a look for me but I think its a no go  

 

[Jammin]

Hey Trailer Boy thanks for the post, I did a home study course to get C&G level 3 and my 2392 if i'm honest I did rush through it a bit so I'm constantly having to check the regs and being a home study course didn't get much practical training so I'm learning as I go.

I didn't take an earth loop reading from what I could see or not see for that matter I believe this installation never had one, as there are no signs of any earthing arrangements anywhere just line and neutral conductors. Would I be correct that in assuming in the old days before the war the dno used the neutral as the earth? that for me might prove a reason why its not there.

I know what your saying about the remedial work spot on! but were talking about a Northern Irish farmer and there notorious for not wanting to part with any cash.

Just to clarify I have nothing against the Northern Irish of farmers just to cover my rear.  

 

[Andy™]

erm... DNO use the neutral for the earth all the time... its called TNCS....

it used to be acceptable to use a metellic water pipe as the earth electrode (although even that may have been wired in 1.5) , but not any more. of course, with proper training, you would know that

 

[Jammin]

Thanks Andy. Noted

 

[steptoe]

with it being a norn iron beerciey type, most probably earthed through a steel upright in the cattle shed somewhere...........

 

[NozSpark]

I've done that before.... Used the steel structure of the barn as the earth electrode,,,,, nothing I would have put in would have been anywhere near as good

 

[steptoe]

TBH Noz, thats what we used ALL the time in farms in NI, if you were lucky and they were putting up a new shed you could sometimes get a grid in before they poured.

 

[steptoe]

:shakehead

Canoeboy didn't spot the magic word,

ASSUME

 

[Andy™]

They are only compatible if

1. You comply with the manufacturers instructions and place special attention to TT notes and calculations in their tech doc 

2. Ra complies with the SMA guidelines

3.You fit a proper Siemens or ABB RCD that SMA recommend in their instructions on TT (and other) supplies

So from this as you have fitted sma TL's to TT installs before then 

1. I am teaching you to suck eggs

2. You know the tech doc I am talking of

3. You are familiar with the ABB and/or Siemens RCD

wonder if he also knows not to put the solar PV on the same RCD as other circuits too

 

[Jammin]

Guys this information is gold to me thank you very much! I will check for earthing in the locations suggested. I am aware of the tech doc and RCD you mentioned, and found out about putting solar on a separate RCD the hard way.

I will go back and have another look and let you know how I get on.

Once again guys thank you, I'm learning a lot!

 

[binky]

if it's that old you may find odd little black cable is the earth, or even just a bare wire - usually stranded, unles CU is metal clad and bolted direct to steel frame.

I would be inclined to install miniCU for your solar connected directly to meter tails, and suitable earthing / bonding, then leave rest well alone unlees you can persuade farmer to part with cash.

 

[Jammin]

Hey binky that would be ideal for me to do what you suggest, just run my own cable split tails into a garage board and install an earth rod and bonding. But my understanding from previous posts is I have to get the whole place up to scratch before I can install the solar.

Spoke to farmer no chance of him parting with cash for remedial work just wants solar, reckon he's got upward of a mill in his bank account brand new tractor and a 1 yr old combine in his shed.

 

[binky]

no, just the earthing and bonding, not the rest of the sh1te electrics.

 

[Jammin]

Thanks for clearing that up Binky.