Bonding the array

[jcarlie]

Evening guys

I know this one has been done to death, just wanted to share my proposal for an installation we are about to install.

Fronius TL 3.6 inverter
PME supply
Velux window, although im pretty sure that the array will not be accessible from this window.

After reading the DTI i have come to the conclusion that if i carry out a R2 test between the array and the MET and record a result of greater than 22K ohms then the array will be classed as isolated from the installation and therefore not an extraneous conductive part, thus avoiding the need to bond the array.

What is the general stance of others regarding this?

Cheers

 

[malcolmsanford]

well you nearly got it ........................... it would be an IR test not the R2 test.

 

[jcarlie]

i meant long test lead method, not R2 ! my mistake, its been a long day !

Thanks for pointing that out Malcolm !

 

[moggy1968]

err, surely it's not an IR test either. Your testing the continuity (resistance if you like) of the array to earth.
banging 500v through the array won't prove anything, except that it has no insualtion resistance

 

[malcolmsanford]

Moggy to test that a piece of metal work is an extraneous conductive part is an IR test, which is where we get the 22Kohm value from.

You IR test between the main MET and the piece of metal work and anything over 22KOhm is not an extraneous conductive part

 

[moggy1968]

sorry, yes, getting my mucking head in a fuddle!
must be too much fursty ferret and a late night!

 

[sedgy34]

bonding the array because of a velux window is because of direct contact, however you say even though there is a velux window the array is still not accessible to direct contact so not required is it. imo (tin hat on)

 

[jcarlie]

I would take the view that if the array is within touching distance of the velux window then it would be in the equipotential zone, if you cannot access the array from the window it is outside the equipotential zone

 

[malcolmsanford]

I can stand by my back door and touch a old pair of secateurs that my lass left there while pruning the roses and are a nice piece of metal.........................where do they stand regards the equipotential zone?

 

[Earthstore]

I can stand by my back door and touch a old pair of secateurs that my lass left there while pruning the roses and are a nice piece of metal.........................where do they stand regards the equipotential zone?

If your back door is the kitchen, it is full of equipment in there, I know because I have seen it while walking through, her indoors spends hours in there..
So if that is the case bonding will be required, or you could move the secatuers further out in the garden..

 

[Gavin A]

If your back door is the kitchen, it is full of equipment in there, I know because I have seen it while walking through, her indoors spends hours in there..
So if that is the case bonding will be required, or you could move the secatuers further out in the garden..

but only while hovering, otherwise you might risk becoming an extraneous conductive part yourself and some passing spark / plumber / kitchen fitter might bond you to the MET before you made it to the secatuers.

 

[moggy1968]

do I need to bond the taps on the kitchen sink if the missus does the washing up in her wellies?

 

[berni]

can someone tell me whats the difference between an IR test and and r2 test and a long lead test ? To my thinking the r2 test is a continuity performed at low voltage with a long lead ,whereas an insulation is at 500v , but whats the IR test?