Electrocuted by roof.

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Scott3

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#270012 19-Apr-2020 17:18

Decided today was a good day to wash the house.

Was up a ladder with a sponge, when I got a fairly hefty electric shock off a piece of roofing steel. Obviously worrying from a safety perspective.

Went back with a multi-meter and measured 236v AC between a nail in the area, and the lawn...

It was raining at the time, and I had already done one lap of the house cleaning out gutters, and was roughly half way around the house the second time with a sponge, so had been blasting water everywhere for most of the day.

Fault has since gone away (down to 7v Ac between nail and lawn).

No breakers tripped. House only has an RCD on the bathroom circuit, and that was not tripped.

Not really sure what to do. Is there any point in calling in a sparky when I can't replicate the fault? Anything they could do to diagnoise.

It may have just been that I got something wet I shouldn't have, and it dried out, but having random bits of the house live isn't a sustainable solution given I have a toddler...

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#2465513 19-Apr-2020 17:22

I'd be concerned that when it rains or the next storm hits that something catches fire. Seems worthwhile to get an electrician in.

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Andib

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#2465515 19-Apr-2020 17:23

Call an Electrician.

If you show them the part that shocked you, they should be able to trace it back to what the source is.

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Scott3

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#2465526 19-Apr-2020 17:37

Andib: Call an Electrician.

If you show them the part that shocked you, they should be able to trace it back to what the source is.

Even if the voltage is no longer present?

snnet

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#2465584 19-Apr-2020 17:51

Scott3:

Andib: Call an Electrician.

If you show them the part that shocked you, they should be able to trace it back to what the source is.

Even if the voltage is no longer present?

Your roof should never come live no matter what you've wetted down

Call an electrician

JeremyNzl

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#2465591 19-Apr-2020 18:01

Interesting read, This has happened before as suggested get a competent Electrician

https://webcache.googleusercontent.com/search?q=cache:S1rkITXoB9oJ:https://www.electricalforum.co.nz/index.php%3Faction%3Dmore_details%26id%3D1439535412+&cd=1&hl=en&ct=clnk&gl=nz

snnet

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#2465594 19-Apr-2020 18:14

A competent electrician is just one that is qualified :)

You definitely want to talk to one confident in fault finding, not just your average house/commercial basher. One that advertises servicing and maintenance.

Zeon

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#2465669 19-Apr-2020 19:31

Can you get into the roof space near the part that was live? Check if any nails through cables etc.?

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mentalinc

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#2465682 19-Apr-2020 19:47

Zeon:
Can you get into the roof space near the part that was live? Check if any nails through cables etc.?

Please don't do this.

Get someone in to fix this for you.

You risk serious injury and people having to break their bubble to help you.

An electrician can manage the bubble to repair for you compared to ambulance staff

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cyril7

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#2465689 19-Apr-2020 20:11

Time of year for mice, the love to eat the tps sheath, leavi g wires exposed.

Cyril

skewt

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#2465702 19-Apr-2020 20:56

How does the mains power enter the house?

Some older aerial connections entered via a metal conduit and the sheathing could become compromised

larknz

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#2465710 19-Apr-2020 21:08

What can happen is that a roofing nail can be put though a lighting switch wire and the roof is only live when the light is turned on. People have been killed by this in the past. This is an essential service to get the fault checked out by an electrician.

gregmcc

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#2465714 19-Apr-2020 21:14

CALL AN ELECTRICIAN - THIS IS NOT SOMETHING YOU AS A HOMEOWNER CAN TACKLE

Things that it could be in most likely order

1) A nail/screw holding the roofing iron on has pierced a wire in the ceiling

2) The element in the Hot water cylinder has developed a fault to earth (split in the element) and the earth wire to this has failed, while heating it livens up the roof through the overflow pipe

3) (most unlikely) there has been a reversal on the incoming phase and neutral causing anything connected to earth to become alive

CALL AN ELECTRICIAN - THIS IS NOT SOMETHING YOU AS A HOMEOWNER CAN TACKLE

once it is sorted out, post back here and let us know

sparkz25

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#2465745 19-Apr-2020 22:00

CALL AN ELECTRICIAN END OF STORY!

I have seen this before in an industrial situation where it was a bad neutral at the transformer.

At another place the main earth was the old galv water pipe that had just been replaced with a new PVC pipe.

It could be one of many things!

So Call a Electrician so they can do the checks that are needed to be done!

JessieB

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#2465757 19-Apr-2020 22:39

The fact that no breaker tripped, and that you are not dead, and the fault goes away when the roof is dry implies that a nail is not responsible for piercing a wire. Instead a relatively small amount of current is flowing through dampness from a leak in the roof, along the roof framing to an exposed piece of wiring. The exposed wiring could be caused by mice or rats, or it could be a poorly installed wiring join. Or the leak could be quite bad, and water is flowing down the inside of a wall to a light switch. An electrician would turn power off using the main switch at your switchboard and then measure the earthing of each circuit to isolate the circuit with the fault.

JessieB

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#2465760 19-Apr-2020 22:49

Should also add that a roof acts like a giant capacitor, so can give a big shock even though the fault is letting through only a very small current.

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