Electrical safety !!

macabethiel · 02-09-2016, 06:46

Was reading through an old post about Electricity when I was reminded of a mishap we had many years ago when we moved into a new (used) house with baby daughter circa 1974.

One Sunday morning at breakfast daughter came into our lounge crying a tad saying the washing machine had bit her !

I promptly went into the kitchen and saw the washing machine an Indesit was running as it should be. I touched the machine to demonstrate it did not bite and got a nice jolt from the casing.

I went to the Consumer Unit under the stairs - it was a two fuse steel cased unit with big pot fuses one for lights one for ring main and switched off the mains. All rusty looking with spiders webs etc.

I checked the washing machine and found that a cable had rubbed against the drum and had worn through shorting against the main bodywork. All steel in those days. Wondered why the fuse had not blown so looked at the consumer unit and found that there was no earth wire connected !

The house had been vacant for about two years the owners had emigrated and the old Electric Board had put in a new PME supply having disconnected the old earth that was some sort of pole stuck into the ground outside!

I connected the Earth to the unit and checked the supply and found that the "Live" was connected to the Neutral and Neutral to the Live side of the old fuse box. As funds were tight did this myself after removing the seal wire loop and taking out the big fuse by the meter box.

There was no case to pursue against the previous owners and the view by the now defunct East Midlands Electric Board was that the Team that did after the Meter never connected the supply after the new PME supply was installed.

Thank goodness Electrical Safety has improved since those days !
Or has it ?

don simon · 02-09-2016, 08:20

Left to our own devices we'd probably still be trying to get away with things like this. Even little things like the EU introducing the fixed plug to appliances is a good thing as it saves me having to check all plugs on new appliances before using them.

makeitfit · 02-09-2016, 09:33

Quote:

Originally Posted by don simon

Left to our own devices we'd probably still be trying to get away with things like this. Even little things like the EU introducing the fixed plug to appliances is a good thing as it saves me having to check all plugs on new appliances before using them.

Fixed plugs are a pain in the arse. Have to cut them off all the time fitting kitchens . I used to be able to recycle them

rustic · 02-09-2016, 16:12

Quote:

Originally Posted by makeitfit

Fixed plugs are a pain in the arse. Have to cut them off all the time fitting kitchens . I used to be able to recycle them

You could leave the plug with a short length of cable and make up adaptors, eg blue 16 A caravan socket, or a two way or 4 way extension sockets.
Watch out for the cable capacity, some are only 6A

Re earths, you can loose earth continuity even without doing any electrical modifications.
Replace a length of copper pipe with new plastic push fit connectors.

Rustic

macabethiel · 12-09-2016, 18:01

Quote:

Originally Posted by rustic

Re earths, you can loose earth continuity even without doing any electrical modifications.
Replace a length of copper pipe with new plastic push fit connectors.

Rustic

Isn't this why PME was introduced ?

rayf3262 · 12-09-2016, 18:30

Quote:

Originally Posted by macabethiel

Isn't this why PME was introduced ?

There are 3 common types of electrical supply systems to domestic and commercial premises.

A) TNC-S A.K.A. PME
B) TNS
C) TT

TNC-S or PME: The supply enters your home as 2 conductors Phase or live and a COMBINED Neautral and Earth. The earth connection provided by your network operator is simply taken from the neutral as it enters the service head, where it becomes SEPARATE. (S)
PME is what happens BEFORE the supply reaches your home, the neutral conductor is tied to ground with earth spikes at many locations en route to your property. The is the MULTIPLE part of PME. This is done as a safety precaution to minimise the risk in the very unlikely event of the neutral conductor being broken along the distribution path.

TNS is a 3 wire system where the operator provides phase, neutral AND a SEPERATE earth connection. This earth connection is an unbroken conductor all the way back to the point of origin (transformer).

TT: is a 2 wire system where the operator provides phase and neutral and NO EARTH.
The earth is provided locally by the customer, typically a ground stake or series of them.
This system relies wholly on the use of an RCD to detect fault current to earth and kill the power in the event of a fault, as it is near impossible to achieve a low enough earth impedance to activate the protective MCB's.
The MCB's will however provide overcurrent protection with phase/neutral faults.

02-09-2016, 06:46	#1
macabethiel Senior Member Join Date: Aug 2008 Location: Derby Vehicle: Freelander & Jeep GC 3.0 Posts: 4,416	Electrical safety !! Was reading through an old post about Electricity when I was reminded of a mishap we had many years ago when we moved into a new (used) house with baby daughter circa 1974. One Sunday morning at breakfast daughter came into our lounge crying a tad saying the washing machine had bit her ! I promptly went into the kitchen and saw the washing machine an Indesit was running as it should be. I touched the machine to demonstrate it did not bite and got a nice jolt from the casing. I went to the Consumer Unit under the stairs - it was a two fuse steel cased unit with big pot fuses one for lights one for ring main and switched off the mains. All rusty looking with spiders webs etc. I checked the washing machine and found that a cable had rubbed against the drum and had worn through shorting against the main bodywork. All steel in those days. Wondered why the fuse had not blown so looked at the consumer unit and found that there was no earth wire connected ! The house had been vacant for about two years the owners had emigrated and the old Electric Board had put in a new PME supply having disconnected the old earth that was some sort of pole stuck into the ground outside! I connected the Earth to the unit and checked the supply and found that the "Live" was connected to the Neutral and Neutral to the Live side of the old fuse box. As funds were tight did this myself after removing the seal wire loop and taking out the big fuse by the meter box. There was no case to pursue against the previous owners and the view by the now defunct East Midlands Electric Board was that the Team that did after the Meter never connected the supply after the new PME supply was installed. Thank goodness Electrical Safety has improved since those days ! Or has it ?

02-09-2016, 08:20	#2
don simon Senior Member Join Date: Oct 2014 Location: Gone. Vehicle: Terrano ii Posts: 2,215	Left to our own devices we'd probably still be trying to get away with things like this. Even little things like the EU introducing the fixed plug to appliances is a good thing as it saves me having to check all plugs on new appliances before using them.