Assesment At 1Pm

[Evans Electric]

OOOo...EEeeee    I just can't wait for more rules & Regs being imposed on us ..........oh what fun we will all have in the new year  ... must start saving my money  for that shiny new Regs book  ...and I can bin yet another £70 quids worth and then wait while some committee dreams up some more alterations ...usually timed about 6 months after  you've shelled out your £70 .

Hmmm  those Anti-Cynical pills that Kerch sent me,  don't seem to be working !

Sorry Steptoe I don't follow, what has a TT system got to do with a Consumer unit being made from metal?

Check your Regs on TT system  meter tails entering metal enclosures.

 

[steptoe]

Sorry Steptoe I don't follow, what has a TT system got to do with a Consumer unit being made from metal?

that is first year stuff tbh.   :shakehead

 

[matt hunt]

Sorry its been a while since I did my first year, please elaborate?

 

[steptoe]

I dont know the reg number,

but,

basically, the supply on a TT cannot enter a metal enclosure without advance protection or other adequate measures being taken,

usually accomplised by a 100mA [or sized as required] RCD in an insulated enclosure before the M/C CU

there are other methods of doing this, but most are prohibitively expensive for a domestic environment.

 

[matt hunt]

A TT System needs an RCD switch anyway, which is usually before the Consumer unit! so what has a metal enclosure got to do with it? obviously Electricians need to be aware of eddy currents but this is covered in year 2 work

 

[kme]

Sorry Steptoe I don't follow, what has a TT system got to do with a Consumer unit being made from metal?

Perhaps you should have one of your ( time served) apprentices explain it to you???

:innocent   :C   :coat

n.b Yes. WE know they need an RCD. What type of enclosure are we going to put it in, if plastic is banned???? 

 

[matt hunt]

Thanks for your imput KME, maybe you could elaborate on why a metal enclosure cannot be used on a TT system? sorry apprentices are in bed now

 

[kme]

Sorry Steptoe I don't follow, what has a TT system got to do with a Consumer unit being made from metal?

A TT System needs an RCD switch anyway, which is usually before the Consumer unit! so what has a metal enclosure got to do with it? obviously Electricians need to be aware of eddy currents but this is covered in year 2 work

Thanks for your imput KME, maybe you could elaborate on why a metal enclosure cannot be used on a TT system? sorry apprentices are in bed now

Takings these three posts together, leads me to one conclusion....................and I leave you all to draw your own....... :coat

MH: I will not be replying - I now know how you reply to people who don`t see things "your way".

Good luck with/to remaining members who respond - seem to be less of those then there were to begin with...........

 

[Jono Pashley]

Because if your "rcd" is in that metal enclosure its only protecting DOWNSTREAM of the RCD. Now can you tell me why thats not good?

 

[matt hunt]

Sorry you feel that way KME, maybe a response would of sufficed as it was a question not a statement, I only deal with facts and not silly accusations and certainly will not throw my toys out of the cot if I don't like the answers, maybe I will get an educated answer from someone tomorrow, in the trade.

On a TT System Jono, the RCD is usually after the meter but before the Consumer unit so what is your point?

 

[Jono Pashley]

Point is the metal enclosure could become live and never blow the service fuse due to the loop impedance...

 

[matt hunt]

But the RCD is before the metal enclosure? in series with!

Its a TT System!

 

[Jono Pashley]

So that rcd is just floating around in free air is it............................................................

 

[matt hunt]

O dear!

 

[M107]

FFS  ray

Dont know about being year 1 stuff...even a 5WW sHOuld know this.

 

[Sharpend]

Matt you might want to go back to your assessor and ask him the same question seeing as he advised you? Perhaps we will have a glass enclosure for the rcd!

 

[kerching]

Right, i will put this in terms that even i can understand as i am new to the trade ....ish

Service.......meter........RCD..........consumer unit.........yes?

What material is the RCD enclosure made out of?

Just curious

 

[NozSpark]

Matt..... The Reg in question will be about non flammable enclosures,,, not consumer units

So.... We all agree that a TT system has increased RCD requirements....

Now,, let's say we use a metal CU, any RCD within that CU will only protect the outgoing circuits so the tails won't have any RCD protection.

What do you think will happen if the tails chafe and short to the metal CU?

So to stop this happening we could install a RCD in the tails before the CU, but according to you we have to use a metal enclosure,,,, we end up with exactly the same problem at the RCD.

 

[Sharpend]

Noz do you want a spoon to feed that?

 

[NozSpark]

Noz do you want a spoon to feed that?

It's the only way he's going to understand it