Electrical Question?

[Alexam]

With a router table, sanding machine and scrollsaw all in the same location within reaching distance of a plug socket. The safety of an NVR switch is well known, but is it possible to use one NVR plug connected to the mains socket and then to an extension lead with 3/4 outlets to the three machines rather than an individual NVR to each?

Axminster have an NVR/plug outlet here - http://www.axminster.co.uk/axminster-bs ... tch-103621 but not sure if its meant just to plug in one machine at a time or more machines, bearing in mind that usually only one machine would be running at any one time
Malcolm

 

[Fitzroy]

I don’t see why not, all an nvr has inside is a relay inside that holds the switch closed until power stops. Having typed that, some extension cords have a wee red light on the extension block to show it’s reciving power, that could be enough to hold the nvr closed. If you were running two machines that’d ‘confuse’ the nvr but it’d probably also overload the extension fuse!

F.

 

[Phil Pascoe]

Surely it's the power to the NVR that operates it, not the power demand after it?
So long as the NVR socket isn't overloaded why shouldn't it work just the way it works with one tool plugged into it?

 

[flh801978]

NVR's are generally fitted to machines that would cause serious injury if the power died and subsequently restarted up whilst an operator or onlooker was close.
I would argue that a scrollsaw and a sander are ok without a NVR
Most new handheld routers are not fitted with NVR's anyway ( some are) enabling them to be fitted into tables with remote switching
some of the larger workshop equipment is essential to have NVR's fitted but I'm sure you would be fine with the machines you listed Malcolm without

Ian

 

[Racers]

You could have the scenario where you switched the NVR on and all your machines came on, so individual NVR will be safer.

Pete

 

[Lons]

I've had one for years Alex as I had a spare NVR box I picked up somewhere, it's just wired with a 2m lead & plug one end and single rubber ext socket the other.
It works very well and I've used it on several tools including router and scrollsaw though never more than one machine at a time. Don't see why it can't be several machines but as Pete says there's a dager you might turn off the NVR rather than the tool and next time more than one starts up. Not worth the risk.

I went to take a pic of it but forgot that I've since fixed it under my router table.

Bob

 

[Rorschach]

I don't see why not. Similarly you also see foot switches wired into a machine, I found this impractical so wired a foot switch into an extension cord, works great and allows me to move it between tools for specific jobs. It's a bit annoying for tools that have a built in NVR switch, but for certain jobs it adds more functionality and safety since it acts as a dead man switch; press pedal, turn on tool, use tool and if you lift the pedal the tool stops and won't start again.

 

[Alexam]

Thank you all. Very helpful.

 

[sunnybob]

What youre talkng about is a panic button, officially known as an "emergency stop" like this

http://www.jtmplumbing.co.uk/heating-co ... ves-p22052

This is wired into the whole socket circuit.
Then each machine can be used with its normal NVR switch. In the event of an emergency, or simply as you leave the shop at night, you hit the panic button which kills all power outlets.
Next morning you twist the button to reset, and any machine with an NVR still needs to be started as usual.

 

[Lons]

What youre talkng about is a panic button, officially known as an "emergency stop" like this

http://www.jtmplumbing.co.uk/heating-co ... ves-p22052

This is wired into the whole socket circuit.
Then each machine can be used with its normal NVR switch. In the event of an emergency, or simply as you leave the shop at night, you hit the panic button which kills all power outlets.
Next morning you twist the button to reset, and any machine with an NVR still needs to be started as usual.

Yebbut surely if you had more than one machine plugged into the NVR and all were on at the individual machine switches then all of them would start up when the NVR was switched on which could be dangerous. Or is that not the case?

Bob

 

[sunnybob]

No, thats the whole point of No Volt Release switches, when the power is cut for whatever reason, the switch disconnects and will not restart unless the button is manually pushed.
The panic button will kill the circuit, thereby automatically turning off any machine operated by an NVR switch.

 

[Phil Pascoe]

Yes, but you're presuming everything has it's own NVR, and if that is so the original question is redundant - you'd just plug them all into an ordinary extension.

 

[sunnybob]

having re read the first post I see that Malcolm wanted to use a single nvr for multiple machines. i mis read that as wanting a single on off switch for multiples. Thats why i put forward the panic button.
The NVR malcolm listed at the start is only rated for 2000 watts. OK for smaller multiple tools but not if theres a big router in there as well.
But the "safety" aspect of an NVR isnt to protect the operator, its to prevent the machine restarting by itself after a power outage. It doesnt have any effect on electrical faults down line from the switch. So connecting several machines to a single NVR is no more or less safe than any single machine.

An rcbo :
http://new.abb.com/low-voltage/products ... vices/rcbo

in the main box is the safest method of workshop protection.

 

[Alexam]

Thanks Bob, it was'nt what I was thinking, but that is also a good item to have in a shop. However, it usually kills everything and some things I leave on all the time, like the humidifyer (fantastic machine) and occassionally a heater when it's really cold. Something you don't often get over there! :lol: :lol:

It's just that I will be getting an NVR for the new 3.5 hp router and was thinking about other bits as well to use with an extention block.
M

 

[sunnybob]

Cold? oh yes we have cold. Its down to 25c today and I'm FREEZING! I even had to wear long trousers last weekend!
But we do have a dehumidifier, and it is amazing how much water can be removed by one.

I dont see anything to gain from having an NVR switch controlling extension leads with other machines. As said, the NVR is NOT a personal safety device, it wont protect you from electric shock.
If that is your concern, you would be better off with this type of thing
https://www.ebay.co.uk/p/Fa-24-Hour-Deo ... 1011685165

 

[Alexam]

Cheers Bob, I had the garage completly rewired with RDC breaker, but kept one double plug to the house just in case of problems, so two circuits. Not concerned, just trying to cut a few corners. The NVR switch mentioned can be used for the router, but could change plug-in to another machine if needed. There is already one on the scrollsaw, the bandsaw and the P/T and I still have 10 digets.
Malcolm

 

[sunnybob]

all safety is good safety. i've worked on many machines in the distant past that suddenly came alive while my hands were inside. It took me a few lucky escapes to learn, but I am extra cautious and just fit NVR switches to every fixed machine, and always unplug before I take covers off.

I have to bring them from the UK. A stand alone NVR switch here has a a 75 euro price tag attached. See, its not ALL paradise.

 

[Alexam]

:lol: :lol: Ahhhh but you can stock up when you come back for a visit ......... not so hard done by I think!

 

[sunnybob]

c;mon, I need something to moan about. How can I be a grumpy grandad without something to whinge over?