Bonding between Earth blocks on Hager Invica boards. Is that it?

[Mark42]

I’m today fitting a Hager Invicta TPN board; the first time I’ve used this model.

Maybe I’m missing something here, but the four earth blocks sit on heavily-painted steel brackets, with the only electrical connection between the blocks and main earth terminal via the chassis, relying on two BZP screws, tapped into punched holes, themselves full of paint.

There is no local removal of paint, no cross-bonding cables or links, and no obvious provision for fitting them yourself, since all terminals are numbered, with the lower two blocks having no spare ways.

Is this adequate? Steel rusts, BZP corrodes, the contact area must be tiny: it feels wrong.

What’s the point of fitting bloody great earth conductors, with crimp terminals torqued down onto M8 bolts, if the current path then progresses via weedy little screws?

Opinions?

 

[Notsosmart]

What does the manufacturers blurb say (if anything.) If you are concerned try undertaking a continuity test between earth bars.

 

[Mark42]

The blurb is silent on this.

Of course I checked continuity - it's fine (0.4Ω or so) as would be expected - I wasn't suggesting there was no connection at all - that would be a gross design defect.

But the current path going via rubbish little self tappers under maybe heavy line to earth fault conditions feels wrong.

The paint is non-conductive by the way.

Cheers, Mark

 

[telepath]

Perhaps terminals B4, B5 and B6 are for linking the earth bars, an earth to the chassis and your main earth.

 

[Notsosmart]

Perhaps terminals B4, B5 and B6 are for linking the earth bars, an earth to the chassis and your main earth.

Only now have I looked at the attached photo

You must have read my mind Telepath Bonding points, so use one from each bar back to chassis stud & terminate main earthing conductor to chassis stud.

As for manufacturing foibles well if its to BSEN that's all that matters....Isn't it? (They've covered their behinds so make sure you do like-wise.)

 

[Mark42]

I initially thought that too, but the lower pair of earthing strips (not in photo) are labelled only 13-24 and 37-48 with no ‘spare’ ways, labelled ‘B’ or otherwise.

So clearly the manufacturer provides the ‘B’ ways solely for the bonding of extraneous parts, and relies on the weedy, coarse-threaded screws for cross-connections between the bars.

Additional bonding is exactly what I’ll do, but it shouldn’t be necessary on an expensive board! Has anyone else come across this issue?

Agreed also that just because it’s BS- (Yeah, BS, exactly!) doesn’t meant it’s right! I always take approvals/regulations/guidance with a pinch of salt and sometimes engage my own intellectual apparatus instead. Occasionally this works

 

[davelerave]

they need linking defo