Garage supply

[sparkyb]

When wiring a garage should i wire the mains cable into the trip side of the board to protect the cable going to the garage or should I come of the main switch side so that the trip is in the garage and if it blows only the garage will go off.
I was thinking the first way so that the cable is trip protected?


Thanks

 

[Hawk81]

I would like to know the reasons why people are so against exporting earths to outbuildings on tnc-s.

You and me both! Seems to be a common misconseption that it can't be done. Then when they can't say why they revert back to "the DNO don't like it" which is rubish.

 

[telectrix]

DNO don't like anything they're not making buckets of cash from

 

[telectrix]

1 example of DNO greed. customer was experiencing serious volt drop on supply , 205V measured with hardly any load. DNO said they couldn't do anything about it, rural area, long way from sub, blah, blah, but were extremely happy to install a 3 phase supply for £15,000.

 

[Geordie Spark]

Another example:

House supply is looped from next door on two bits of VIR approx 6mm csa.

DNO is coming to change the VIR to comply with modern standards, but will only change like-for-like, meaning that there is no earth provided with the old VIR cables & there will be no earth provided with the new cables either ...... unless the customer pays them £150.

 

[Electro-tech]

Exporting PME !
What if the supply neutral or PEN conductor was broken upstream of the installation.
What currents would flow through the CCU to Earth. What about diverted neutral currents.
Are you extending the equipotential Zone.
Are you exporting earth fault problems to another building.

 

[Deleted member 26818]

Exporting PME !
What if the supply neutral or PEN conductor was broken upstream of the installation.
What currents would flow through the CCU to Earth. What about diverted neutral currents.
Are you extending the equipotential Zone.
Are you exporting earth fault problems to another building.

It would be no different for the buiding with the exported earth than for the main and any neighbouring buildings that are on the same supply.
However I would point out, that within the industry, broken PEN conductors are not considered much of a problem.
The main problem with exporting a PME earth, is whether there are extraneous-conductive-parts that will require bonding at the exported earth location.
Installing an adequately sized bonding conductor can be prohibitivly expensive.

 

[malcolmsanford]

^^^^^^^^^^^^^^^^^ And that is the whole PME scenario in a nut shell

 

[Electro-tech]

Thanks to Spinlondon, however it will still be the installers preference to a point.It was suggested back in 2002 from memory,somewhere that you could connect a earth electrode at the supply head MET to reinforce the earthing. This topic will still go on.

 

[Deleted member 26818]

Many other countries that use PME sometimes known as MEN, require an electrode at each installation.