Wiring a Fused Fan Isolator

[333rocky333]

What about if someone should replace the fuse?

Table 537.4 states a fuse is suitable for isolation

 

[bernardgreen]

What about if someone should replace the fuse?

The engineer ( or DIYer ) keeps the fuse with him.

As for the rest of Whinny's Wubbish

 

[SUNRAY]

What about if someone should replace the fuse?

But that won't happen because according to the regs removing the fuse is an acceptable means of isolation and according to Winston 1 the regs always usurp everything else and therefore no one would even think about replacing a removed
fuse.

 

[SimonH2]

And in any case, many (most ? all ?) such fuse holders can be locked out with your lock-out padlock. You do all have (and use) appropriate lock-outs don't you ?

 

[SUNRAY]

And in any case, many (most ? all ?) such fuse holders can be locked out with your lock-out padlock. You do all have (and use) appropriate lock-outs don't you ?

Certainly do but I've come across many BS1362 fuse holders which cannot be locked.

In one building I locked out a 3phase isolator supplying a 55KW chiller pump. Because it wasn't one of the onsite electrical contractors 'approved' locks, ie there wasn't a spare key available in their stash, and someone complained a pump wasn't showing as available on the BMS my lock got cut off. At the time I was replacing the pumps local isolator and got a tingle. I then had a predicament, I didn't have test kit to hand [already proved dead and colleague using kit elsewhere], I suspected I had a live wire with no safe means of making it safe so I couldn't risk walking away from it. I tried sending text messages to several people from an area several floors below ground level which also made a fallacy of the lone working monitor/2way radio. Fortunately my colleague returned fairly quickly and was able to isolate again and relock.
CCTV revealed the culpret...

 

[SimonH2]

I hope the culprit was dismissed on the spot.

A friend of mine has a tale of when he was sent to a mill somewhere in Lancashire where many machines were staffed by (mostly) cheap rate immigrants on piece rate. The electrics were old and the isolators in the meter room had no lock-offs, plus each fed more than one machine. Best he could do was hang a notice on the switched-off isolator ...
Gets back to the machine he was working on, to find it live - gets back to switch room to find sign on floor and isolator back on. Repeat a couple of times. So he switched off, hung the sign, and waited out of sight - and it wasn't long before the operator of another machine ran into the room to switch back on again, and was promptly introduced to my mates fist.
Machine operator was dismissed instantly, and my mate was given an escort off the premises for his own safety.

I was also told a tale from when many years ago when a microwave "over the horizon" link was being set up to north sea oil rigs. These basically worked on teh basis of send massive amounts of signal, and some of it will get to the receiver via scatter - peak pulse power measured in MW but a low duty cycle.
So one guy removes all the safety links/fuses and takes them with him when he goes to do some work in the waveguide. Meanwhile, someone else comes along, assumes the fuses/links have just been nicked, finds some spare ones, and powers up the equipment.

Sobering examples why proper locking off is needed, as if we needed any.

In your case, whoever cut the lock off should have been charged with attempted manslaughter. In the cases I've given, whoever was the responsible person (before the term was in use) was clearly guilty of not having safe working practices in not having lock off facilities or an alternative means of ensuring something stays off.

 

[bernardgreen]

Way back in the 1960's on board a ship repairing damaged waveguide and cables between radar antenna and the radar cabinet behind the bridge,

We were the radar manufacturer's authorised service agency in the UK

We had set the power control on the bridge console to Stand_by, This meant that the control circuits were powered allowing the cables for the scanning motor and positional feedback system to be tested with the power to the magnatron switched OFF

Then we heard the magnatron starting up. With the wave guide removed a lot of micro wave energy was about to be released into the room making it a large micro wave oven.

The captain had turned the key from Stand By to Run. His reasoning was that normal operation of the radar from OFF required Stand-By for 15 (?) minutes warm up time and then Switch to Run. Having seen the switch in Stand-By for more than the required warm up time he followed the manufacturer's instructions and switched to Run. There was a language problem and we could not get the message across to him. We ensured the magnatron could not be powered up by cutting internal wiring to it and then left the ship and notified the shipping agency and the manufacturer.

With no working radar the ship was not permitted to sail and was effectively stranded in the dock until we felt it safe to return and finish the work with a suitable person remaining on the bridge to make 100% certain the captain did not touch the radar console while we were on board.

 

[winston1]

Back in 1971 when working in Australia we had a “danger tag” system. When an isolator was turned off everyone working downstream tied a signed danger tag to it. Anyone switching on with danger tags attached or taking other people’s tags off was dismissed. Anyone going off shift and leaving their tags on lost 2 weeks bonus. Seemed to work well.

 

[SUNRAY]

I hope the culprit was dismissed on the spot.

A friend of mine has a tale of when he was sent to a mill somewhere in Lancashire where many machines were staffed by (mostly) cheap rate immigrants on piece rate. The electrics were old and the isolators in the meter room had no lock-offs, plus each fed more than one machine. Best he could do was hang a notice on the switched-off isolator ...
Gets back to the machine he was working on, to find it live - gets back to switch room to find sign on floor and isolator back on. Repeat a couple of times. So he switched off, hung the sign, and waited out of sight - and it wasn't long before the operator of another machine ran into the room to switch back on again, and was promptly introduced to my mates fist.
Machine operator was dismissed instantly, and my mate was given an escort off the premises for his own safety.

I was also told a tale from when many years ago when a microwave "over the horizon" link was being set up to north sea oil rigs. These basically worked on teh basis of send massive amounts of signal, and some of it will get to the receiver via scatter - peak pulse power measured in MW but a low duty cycle.
So one guy removes all the safety links/fuses and takes them with him when he goes to do some work in the waveguide. Meanwhile, someone else comes along, assumes the fuses/links have just been nicked, finds some spare ones, and powers up the equipment.

Sobering examples why proper locking off is needed, as if we needed any.

In your case, whoever cut the lock off should have been charged with attempted manslaughter. In the cases I've given, whoever was the responsible person (before the term was in use) was clearly guilty of not having safe working practices in not having lock off facilities or an alternative means of ensuring something stays off.

He was escorted off the promises and it went to court, I know it was custodial but never knew the final details.

Fortunately the procedures in place were to use rubber mats and i suspect that reduced the shock to a tingle.