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Mitre Saw moulded plug replacement

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Evening all

My dewalt mitre saw stopped working. i replaced the brushes, opened up the casing and checked connections etc. No joy. Ive now cut off the moulded plug and replaced it. The saw now works. My question is why is there no earth wire in the power cable? And am i missing something that would make this newly replugged saw dangerous to use? Thanks all.
 
My question is why is there no earth wire in the power cable? And am i missing something that would make this newly replugged saw dangerous to use?

It should, hopefully be what is called 'double insulated', which means no earth is needed. Look on the label, for the symbol, of a square box, inside a second square box.
 
yes it does. the replacement plug is a white domestic one so obviously without that feature. its got the proper fuse in and correctly wired so should be ok to use im assuming?
 
the replacement plug is a white domestic one so obviously without that feature. its got the proper fuse in and correctly wired so should be ok to use im assuming?

I would fit an unbreakable one, to power tools, vacs, or etc., but yes it should be fine.
 
Cheers. Im clearly not an electrician and sort of assume ill end up being the earth if there isnt one present! Good to know that isnt the case and ill get a heavy duty replacement plug. thanks all
 
Im also perplexed as to how the plug itself could fail. there was no visible wear around the cable joint or anything obvious like that and its never got wet (insofar as i know). seems odd that something that inert would fail when all the cheap as chips plastic clips and mountings inside the saw itself, which must get jolted around, seemed to be fine.
 
Im also perplexed as to how the plug itself could fail. there was no visible wear around the cable joint or anything obvious like that and its never got wet (insofar as i know). seems odd that something that inert would fail when all the cheap as chips plastic clips and mountings inside the saw itself, which must get jolted around, seemed to be fine.

Did you try replacing the fuse, with a known good one? If not the fuse, maybe the fuse-holder contacts splayed out, loosing contact.
 
yes tried a few good fuses and different sockets but in the end complete new plug fixed it so something is loose in that plug. it happens i guess.
 
The inner cores of cable often break where they flex the most, usually where they enter the plug or the appliance. I would guess that you cut off the broken core when you cut off the plug and made good when you fitted the new one.
 
Screw fix do a good heavy duty plug - 68744
 
Cheers. Im clearly not an electrician and sort of assume ill end up being the earth if there isnt one present! Good to know that isnt the case and ill get a heavy duty replacement plug. thanks all
If you think about it, you're closer to death when you're moving a plugged-in cable than at most other times in your life, as there is maybe a millimetre of plastic separating your hand from 240v of heart stopper

I've had comments from people that wouldn't dare go near the main electricity incomer board to switch the main isolator off ("because it's dangerous and electricity can kill"), yet they've wandered round the house hoovering with a coil of flex in their hand for years..

The presence of an Earth core in the cable doesn't save them if it's just the live core that's nicked, the electric shock curling their muscles around the cable such that they can't let go no matter how much their brain wills their fingers to open up, so instead protective devices have evolved to the point where they measure the electricity flow out and back and any imbalance is assumed to be a leakage, potentially through a person, and a disconnect occurs. It's thus actually safer to have one of these than it is to have Earth at all, which as a safety system is supposed to be a parallel-with-the-live network of connections meaty enough to blow a fuse/trip upon any failure that results in a short circuit (the washing machine leaking into the motor for example, bridging live to the metal case, which is earthed) of large enough current (and it needs to be a sizeable current; 14A won't blow a 13A fuse particularly quickly, if at all, but 1A is enough to kill a person)

The double square box Harry refers to is an indication that an appliance has been designed in such a way that even if some failure occurs that breaches one layer of insulation inside, there still isn't any touchable part of the outer casing that can become live. That metal screw you see holding the motor case on? There isn't a single failure point that mrans it could shock you. In the old days your metal/cased drill had to have Earth connected to that case just in case it failed in some way, say the bearings fell apart, the armature dislodged, it ended up bridging live to the case and a huge current flows to Earth (which hopefully is well connected all the way back to its earthing point, possibly a metal spike in the ground that hopefully hadn't rotted away to nothing over the years) blowing the fuse If the earth system had silently failed, well.. it's never tested until the point that it's called upon is it? (And you became the Earth connection)

In summary; Earth doesn't offer you anything like the protection you think it does, and there are better methods these days. If your supply to the saw doesn't have an RCD anywhere along it you would be strongly advised to fit one (and it can be in a plug on the saw - Screfix code 63731 - between saw plug and socket - 44855, in the socket it's plugged into - 3133J, into a sub consumer unit feeding the workshop - 453VF etc) just because of risk of damage to eg that millimetre of plastic on the cable that power tools "enjoy"
 
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Where I used to work the company had 'Domestic' and 'Equipment' 240v power outlets in the equipment rooms. The 'Domestic' sockets where on the walls and the 'Equipment' sockets on some equipment 'racks' (skirtings/kick strips) but also labeled as only for approved use. Those sockets were supplied via an isolating transformer and the 'protective' earth connection was from the equipment earth 'plane'. That earth plane was different to the 'Normal' mains earth by around 20 Ohms (a dirty great big resistor) - one end connected to the earth plane and the other connected to the building earth rod by 16mm cables.
One day I'm sitting in the equipment room office when the Trip switch in the power cabinet (where the isolating transformer is located) trips and most of the computer equipment stops working. As the floor manager I have a wander around the floor to find out what was the likely cause before resetting the trip switch to find a builder chap who I didn't know was using power tools outside of the equipment room but on the floor was trying other labeled sockets to get power. He wasn't happy when I pointed out the labels next to the sockets, even more unhappy when I told him he shouldn't be using those sockets for his power tools; he then told me the other sockets on the floor weren't working either, I sent him off to the my employers electrical workshop with his power tools and extension leads together them tested. When he came back I couldn't tell if he was happy or upset as one tool the workshop condemned as dangerously unsafe and the leads on a couple of others needed changing due to the insulation being fractured at the plug or tool end.
I had a chat with the electrical workshop people as part of my report to building officer - they told me that the cable ends had odd strands of the individual cores poking through the core insulation and touching when flexed. Couldn't determine which of the cores shorting caused the trip but all three core had similar problems.

So yes the 'Earth' wire may help protect you but it's not the be all and end all of electrical protection.
 

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