Expect the Unexpected

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PaulSC

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I thought I'd share something I experienced just before Christmas as I thought it might be useful for some of you new to the industry. The older guys on here will have much better stories to tell.

CU change in small mid-terrace house. Only one ring final, two lighting circuits, cooker and heating so in and out in no time - or so I thought.

Prior to starting work everything worked fine. The young couple had just moved in and wanted some piece of mind so new CU and switch plates throughout.

Took out the old Wylex fuseboard and began replacing sockets and switches while the installation was dead. Took a bit longer than normal as I found a few faults which needed recifiying.

Installed the new CU and began dead testing. All fine apart from the ring final which showed IR dead short L-E :C Removed all sockets and checked for pinched/damaged conductors. Everythings fine :C Use my CalCard to check the meters reading correctly. All as should be. :C Now I'm confused as everything was fine a couple of hours ago. Then I see the couple in the back garden pointing and throwing things at the roof. Curious, I pop out with my brew to compose myself and they tell me a squirrel moved in just the day before (I think you can see where this is going).

I wasn't expecting this type of install to have ring final running into loft as the first floor had floorboards, but thought I'd have a look anyway. Lifted the loft hatch and there was our furry friend staring at me (squirrels make some weird noises when ****ed off). After persuading him to move with a broom I had a good poke round. Now were getting somewhere. Found two 2.5's dissappearing under a boarded area. Chased the cable back right into the eaves and there was a good 2 inch section where the conductors were completely exposed. Bingo. Replaced the damaged section and IR now >299 mohms.

Finished the install and showed the owners the damaged section. They were stunned that these furry little fekkers could do so much damage in such a short time. They had someone out within hours to deal with them as obviously they could do the same again, though at least now they have RCD protection.

Moral of this story? Well there isn't one really, it's just that things don't always go to plan (hardley ever for me). Expect the unexpected. Especially if you don't have years of experience to fall back on, which I don't. This all happened within an hour or two.

1. I wasn't expecting such a poor IR reading, but I knew something was wrong. I paid good money for my Megger, so I have to trust what its telling me. It would have been easy for me to simply disregard the reading and energise the circuit, when things would have gone seriously pear shaped.

2. I wasn't expecting the ring final within the loft. But I didn't wire the house so I can't make that assumption. It was in there and so was the fault.

3. One of your best tools is your gob! Talk to customers when things look hopeless. What's changed and when did it stop working? Even the most suposedly complex problems are usually solvable.

4. Why don't squirels fry when they bite through mains cable?

BTW No animals were harmed during this install. The broom was merely for self defense :innocent

 
Squirrels are crazy little critters. what is about PVC they like so much?

Maybe its a good idea to start carrying some nuts in your toolbox

 
I have a CU change in a bungalow coming up shortly and I know that the ring finals run thrugh the loft as I've had a look and I'm looking forward to doing an IR test as I know squirrels are present in the owners garden but where the little so and so's sleep is another thing..I will keep you posted. :Salute

 
4. Why don't squirels fry when they bite through mains cable?
They wait for a spark to come along and turn off the electricity. Many sparks actually carry them around in their vans, unknown to themselves. They can be very crafty creatures.

Incidentally they do make good eating, I am reliably informed!

 
The theme of " Expect the Unexpected" is a good thread actually. Could get some interesting posts.

I switched off a factory once to connect a new switch/fuse to the busbar chamber. Switch back on..... nothing works.... immediate thought, what have we done !!... remove chamber cover and apply testers...nothing ....open main switch and check 500A fuses.....OK.... testers on main incomer ... dead... go outside and look up & down street ..... power cut !!!!!!!

This trade is awash with such things because as you say we don't "Expect the Unexpected"

 
Think we should change the name of this thread to "Tails of the Unexpected!":p

 
Must be squirrel season - I had a callout for blowing lighting MCB 2 days ago - this also turned out to be furry critters chewing cable until they dead shorted it live to earth. S'funny how they (and mice) always seem prefer the live side of FTE. What also made me laugh was thay had been pinching the loft insulation, no doubt to make a nest somwhere.

 
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