Would you accept a Ze of 199Ω on a TT Installation which also has an RCD.

[PEG]

...I've been in countless filling stations,where people are using their mobile devices,and engines are left running.

The most i have ever heard the staff say,is "Points card,sir?"....:conehead:

 

[Jonspark]

...I've been in countless filling stations,where people are using their mobile devices,and engines are left running.

The most i have ever heard the staff say,is "Points card,sir?"....:conehead:

don't really think it's an issue though, not heard of any petrol stations blowing up in the UK.

 

[JD6400]

I was in Thame service station last year filling up and the tanker was there unloading at the same time . The next thing I know is the driver running across the forecourt after a skip waggon playing bloody hell !?

The skip waggon did not stop , and as the tanker driver was walking back past me he noticed that I was a little bemused , it turned out that the skip waggon driver had just filled up on a self service pump probably whilst still smoking because as he had reversed out to go off ( he had been in a car place and not a dedicated lorry one ) , he had flipped his tab out of the window at the feet of the tanker driver whilst he was still unloading !!!!
The old boy was still raging and said that it was a criminal offence and that he was going to get the video evidence and take it further .

 

[Engineer54]

don't really think it's an issue though, not heard of any petrol stations blowing up in the UK.

Nor i, it was always a precautionary rule that was generally adhered to in the day's when the petrol station attendants used to fill your car/bike etc at filling stations.... I imagine it's now ALL self service at filling stations in the UK... Not so in Cyprus, all are still attendant service from around 7am up until around 7-8pm then goes over to self service...

You need to see some of the filling stations i've seen in the Middle East and Asia, death traps just waiting to happen, you want to get in and out of there as quick as humanly possible!! And Yes i've seen a few of these establishments go up over the years, not at the time mind you, just seen the results of the aftermath!! lol!!

 

[Jonspark]

Think it's more of an issue at chemical plant off loading points with liquids such as vinyl acetate not diesel/petrol with different ignition points

 

[Engineer54]

Think it's more of an issue at chemical plant off loading points with liquids such as vinyl acetate not diesel/petrol with different ignition points

Nope, it's a very real issue at fuel storage depots, it'll be a tin tack job for a driver filling up a bulk storage carrier without first equalising his tanker to the depots equipotential zones pipework. I dare say the same would be the case at filling stations. Many people think that diesel tanks aren't that dangerous, but forget that highly volatile diesel fumes found at the top of all diesel tanks can be just as dangerous as petroleum as far as ignition points/values are concerned...

 

[Jonspark]

Nope, it's a very real issue at fuel storage depots, it'll be a tin tack job for a driver filling up a bulk storage carrier without first equalising his tanker to the depots equipotential zones pipework. I dare say the same would be the case at filling stations. Many people think that diesel tanks aren't that dangerous, but forget that highly volatile diesel fumes found at the top of all diesel tanks can be just as dangerous as petroleum as far as ignition points/values are concerned...

yes it's obviously an issue at storage depots, but i meant more the issue of phone use at filling stations compared to chemical plant off loading points.
at some off loading areas your not allowed to walk through with a battery powered pocket calculator!!

 

[Engineer54]

Well these days the ridiculous seems to becoming the norm....

 

[Jonspark]

well in theory these do have the joule/watt energy to ignite some types of flammable vapours. And you don't want to be around when a 100M3 vessel goes up.This has happened in the past, a few been in the US, but there was one explosion in the north of England can't remember the sites name at the moment.
Flixborough in 74

 

[baldsparkies]

Another myth is the one surrounding risks relating to mobile phone use on a petrol forecourt.
I asked the question twice, once when a Gilbarco engineer was on his mobile, and the second was weights and measures.
Both were of the same opinion.
There is no evidence to support the use of a mobile poses any danger ??
Not saying they are right, but I have never found anything that would say they are wrong ???

 

[Geordie Spark]

don't really think it's an issue though, not heard of any petrol stations blowing up in the UK.

Don't start giving these ISIS Jihad types any ideas for fooks sake!!!

 

[Geordie Spark]

Re: Would you accept a Ze of 200Ω on a TT Installation which also has an RCD.

Do you mean Ra

I was wondering about that but didn't like to mention it - me being "just" a plumber an' all ........ :laugh::angel_smile:

 

[Jonspark]

Don't start giving these ISIS Jihad types any ideas for fooks sake!!!

As silly as it sounds it has been taken in to account. Many chemical plants and gas facilites do have a police presence, as is in the Grimsby area.

 

[DPG]

Doesn't really matter if actually using the phone or not - if it's switched on in your pocket then it's still polling the nearest bases station and gauging signal strength/tx power etc. And like people have said above, how many explosions has it caused. In fact, I think it was Brainiacs or Mythbusters which tested this theory out by ringing a load of mobile phones in a gas filled caravan. Must have been Brainiacs thinking about it! Daz

 

[DPG]

As silly as it sounds it has been taken in to account. Many chemical plants and gas facilites do have a police presence, as is in the Grimsby area.

The east Yorkshire coast one near Holmpton/Withernsea has armed police patrols in the area. Can't remember the name of it. Daz

 

[Jonspark]

Yeah went past there other week on way to Patrington caravan park

 

[DPG]

Nice area around there. Nice bit of military history at Kilnsea and Spurn point. Daz

 

[baldsparkies]

Don't start giving these ISIS Jihad types any ideas for fooks sake!!!

Remember when working at a nuclear power station just after 911.
Security was tighter than the proverbial ducks bottom.
We needed to change a supply source during a re furb.
UPS system for comms was signed off as being healthy, and we were give permission to shut down, lock off and transfer.
We were there as a contractor, and the in house maintenance sparks were also present.
All good to go says the in house sparky's with a thumbs up.
No problem bud, says I.
As soon as you throw the switch we will start the transfer.
Oh !! right ok he says.
Ker clunk,
Should of had a full half hour, system went down in less than five minutes.
Now back then if comms go down, all hell breaks loose.
The UPS service engineers were for the high jump, and when they asked who had isolated the supply I was able to say "I know nothing senor"
Moral of the story.
Don't be the scape goat for somebody else's responsibility.:ack2:

 

[Jonspark]

Quite like spurn point but it's a bloody long walk now.

 

[DPG]

Have they not rebuilt the road yet from last year?

 

[Jonspark]

do you can only drive as far as the twitchers hut, then its a long walk to the end

 

[DPG]

Cheers. Do you think I would get down on my Armstrong? (off-road bike, road legal though)

 

[Jonspark]

Cheers. Do you think I would get down on my Armstrong? (off-road bike, road legal though)

should do, although it can be quite sandy in places

 

[Jonspark]

on the other hand i think all motor vehicles might be prohibited

 

[DPG]

Been down before on the bike - it's OK, it does sand ! I guess they might be stopping all vehicles. I'll check before I go next. Cheers, Daz

 

[Deleted member 9648]

Re: Would you accept a Ze of 200Ω on a TT Installation which also has an RCD.

That's what happens when the old bugger doesn't put his glasses on.
Many thanks for correcting me kind sir.
Just wish they could come up with some decisive information or even come to a reliable conclusion as to what makes a max value stable and then at what point its not.
I have corrected TT system readings above 400 ohms.
And yet the 30ma rcd's protecting those circuits have, under test, operated within 40ms/200ms no problems.
If un-stability is a science it needs practical clarification so that we have a definitive cut off value that all adhere to with no grey areas.
In the mean time I will continue to go with 100 ohms purely because logic dictates its a safer bet than 200 ohms.
No other reason, and if someone proved conclusively that below 200 is still a safe option then so be it.

Thats got to be one of the most illogical statements I've ever seen on this forum. You might as well go with 1000 because it's safer than 1667!

 

[D Skelton]

Re: Would you accept a Ze of 200Ω on a TT Installation which also has an RCD.

Thats got to be one of the most illogical statements I've ever seen on this forum. You might as well go with 1000 because it's safer than 1667!

Like saying "I'll only drive at 190mph on the autobahn because it's safer than 200mph" lol!

And.. 'three'.. 'two'.. 'one'... Eng is back in the room!

 

[7029 dave]

Why do people get so twitchy with TT? first you have to understand the system it an earth to earth system, with an good rod or earth matt, the biggest earth conductor(yes 16mm) I have achieved 2 figures.

 

[richy3333]

Re: Would you accept a Ze of 200Ω on a TT Installation which also has an RCD.

Does everything need to be a poll?

We'll be having designs put to a poll soon!

We should have a poll to find out the answer

 

[baldsparkies]

Re: Would you accept a Ze of 200Ω on a TT Installation which also has an RCD.

Thats got to be one of the most illogical statements I've ever seen on this forum. You might as well go with 1000 because it's safer than 1667!

"In the mean time I will continue to go with 100 ohms purely because logic dictates its a safer bet than 200 ohms".

In context with the rest of the quote it seems logical to me !!
Where a TT system is used I will always attempt to get sub 100 ohm readings as opposed to 200 ohms because its a safer bet.
Is not the whole point to reduce the resistance of the earth return path to a point where stability issues are minimised.
Technically we can often go much higher than that, but I prefer not to always rely on what's technically correct.
Otherwise we can bring into play your own analogy of 1667 or even 1000 which I agree would lack logic, but on paper !!
BS 7671 are looking at values below 200 ohms.
NICEIC have quoted below 100 ohms, as does BS 7430.

Actually BS 7430 is a very interesting read so here's a link,

http://jack.nazwa.pl/doc/UK.17th/BS/BS 7430 Earthing.pdf

With reference to Skelts 200 mph vs 190 mph,
If its a Ferrari, with decent brakes, on a traffic free autobahn !!

GO FOR IT unk: