Picture of the week!™

[RF Lighting]

Here's a little reminder to always test for dead, and never trust an isolator.

If you're wondering what the yellow bit is, it's a brass block from a henley block wrapped in tape.

 

[JohnW2]

Here's a little reminder to always test for dead, and never trust an isolator....If you're wondering what the yellow bit is, it's a brass block from a henley block wrapped in tape.

How did that red one get to be so long - was it never connected to the switch? ... or is there perhaps a join I can't see?

Kind Regards, John

 

[securespark]

Maybe there's some slack where the singles go into the isolator.

Are they DI?

 

[JohnW2]

Maybe there's some slack where the singles go into the isolator.

Good point - that's probably the answer. I should have thought of that!

Are they DI?

Good question - we obvioulsy can't really tell from the pic. They are fatter than the outgoing cores - so, if they're the same CSA (pretty big IF, that!), there is scope for them being DI.

Kind Regards, John

 

[sparkwright]

The outgoing neutral is clearly DI, so I assunme the outgoing reds are.

Certainly looks those outgoing cables have been moved about a bit, if you look at the position of the yellow and blue marker tape.

 

[JohnW2]

The outgoing neutral is clearly DI, so I assunme the outgoing reds are. Certainly looks those outgoing cables have been moved about a bit, if you look at the position of the yellow and blue marker tape.

Outgoing? Aren't they Incoming (i.e. with the fuses on the load side of the switches)? ...or am I being stupid?

As you say, the neutral single clearly is DI. However, given that they are singles, I suppose that doesn't guarantee that the red ones are DI - and the neutral does look a bit fatter than the reds. So I don't think I'd be placing any bets.

Kind Regards, John

 

[Adam_151]

I've done the same in anger when called to an isolator that had burnt out. Though I did write on the front in marker pen. And the office sent them a quote to replace it (which they never bothered with )

EDIT: Is that an Aluminium outgoing armoured?

 

[JohnW2]

I've done the same in anger when called to an isolator that had burnt out. Though I did write on the front in marker pen. And the office sent them a quote to replace it (which they never bothered with )

That's all very well (and it would be even better if one could lock the operating lever, as well as writing on it) but, quite apart from all the obvious comments about safety, certainly in RF's case, it's not just the switch which has been bypassed - the fuse has been bypassed as well, so goodness knows what is protecting the outgoing cable.

Kind Regards, John

 

[333rocky333]

Outgoing? Aren't they Incoming (i.e. with the fuses on the load side of the switches)? ...or am I being stupid?

Yes your right normally they would be supplied at the bottom, though I have witnessed supplies in the top before.
Id quess the outgoing is a 4 core swa judging by lack of earth wire

 

[JohnW2]

Outgoing? Aren't they Incoming (i.e. with the fuses on the load side of the switches)? ...or am I being stupid?

Yes your right normally they would be supplied at the bottom, though I have witnessed supplies in the top before.

Indeed. This case is 'normal', with the Incoming at the bottom.

Id quess the outgoing is a 4 core swa judging by lack of earth wire

Yes, it clearly is a cable which is using metallic armour/ wrapping/ sheathing as the CPC - but that doesn't look quite like an SWA gland to me, so I wonder if it might be some other type of metal-wrapped cable?

Kind Regards, John

 

[333rocky333]

Looks a bit like a CWS gland (external gland), screwed into a steel 25 to 20mm reducer

 

[JohnW2]

Looks a bit like a CWS gland (external gland), screwed into a steel 25 to 20mm reducer

Maybe it's an optical illusion, but to me it doesn't look long enough to be that. I'm sure that RF will tell all in due course!

Kind Regards, John

 

[sparkwright]

Outgoing? Aren't they Incoming (i.e. with the fuses on the load side of the switches)? ...or am I being stupid?

Yes your right normally they would be supplied at the bottom, though I have witnessed supplies in the top before.
Id quess the outgoing is a 4 core swa judging by lack of earth wire

Yes, you're both right, the singles must be the 'tails' feeding the isolator.

Was unjustly assuming it was an isolator for a machine - but having tails going to a machine is a bit unlikely!

 

[Lectrician]

It looks like an old style SWA gland - the type that has no shroud, but is not a CW type. (IMO anyway!).

Certainly looks to be using a 25/20 reducer.

Reds look like singles, but would hope are DI as they are not enclosed below the sw-fuse, the neutral is certainly DI. Makes a change to not see red with black tape used as the neutral! Quite often with maintenance electricians on sites, they will order a drum of cable and use it for everything. They never seem to order cuts.

 

[RF Lighting]

The supply to the isolator is DI singles. They are insulated and sheathed in red.

The outgoing cable is 16.0mm² 4 core copper conductor SWA. The gland is a 32mm gland into a 40mm reducer. It appears to be tin plated brass. It's quite old, but has metric threads so not ancient.

The isolator burnt out at about 6am. A colleague of mine attended site and got the power back on for the customer as this is an essential supply. I attended site the same day and replaced the failed isolator.

The isolator was supplied from the origin protected by the DNO's 80A BS 1361 fuses. The outgoing BS 3036 fuses contained 100A fuse wire.