Safe to use power tools in garage?

[oldbutnotdead]

That about sums it up- especially the bit about getting someone competent/qualified to have a look at it all.
Never a good sign if the lights dip when you fire up a high power device- indicates the cable is undersize for the load. Especially with motors, startup current can be a lot higher than running current.
If you're struggling to get someone you trust to do the work, that Martindale that someone linked to will at least show you whether you have a functioning earth in the garage (or in the rest of the house)
Occasionally prodding the TEST button on the ELCB wouldn't be a bad idea.

 

[JohnW2]

- I need to get an electrician out to answer that and most likely do some remedial work
... To be honest given your views of what I've shown you (which is the handy work of three different electricians), I'm not sure if I can even trust anyone I call out but I guess I'll have to take that risk if I want to realise my dream of accidentally lopping my tits off with a table saw

That's always the problem. The usual advice is to seek tradespeople (be they electricians or whatever) on the basis of personal recommendations from people who have been satisfied with their work but the catch with that is that most people are only able to assess superficial aspects (tidiness, neatness, punctuality, politeness, reasonable price) etc. and not the 'electrical competence' (or even safety) of the work.

I suppose the safest of all would be to try to find someone who had done work that not only satisfied the customer but whose work had, for whatever reason, been subsequently inspected by some other electrician without any appreciable adverse comments - but such an animal would probably be very hard to find.

So, as you will imply, there is nearly always going be an element of 'gambling'. The 'personal recommendation' method is probably the best, at least in a 'negative' sense - since if an electrical is, for example, untidy and/or does work which is clearly not neat, then there is clearly going to be some doubt about the (electrical) quality and competence of their work. I would certainly suggest that you avoid 'tradesman recommendation websites' etc., since they are so easily abused and manipulated as to potential be 'worth less than nothing'!

Kind Regards, John

 

[John D v2.0]

Never a good sign if the lights dip when you fire up a high power device- indicates the cable is undersize for the load. Especially with motors, startup current can be a lot higher than running current.

I didn't realise that - our lights dip with the vacuum cleaner or the mitre saw starting up, even on different circuits. The PSSC is something like 800A from memory so nothing too close to the limit.

 

[chivers67]

That's due to the pull of the start up current due to the motors they both have.

 

[JohnW2]

I didn't realise that ...

Nor me, and I think that's because what oldbutnotdead suggested can't possibly be true.

Inadequacy of cable size within the final circuit supplying a particular load can result is problems (for that circuit/load) of VD during high start-up currents. However, to affect (result in a VD in) other final circuits (like lighting) would require a VD upstream of the origin of the final circuit (i.e. somewhere common to both circuits)

- our lights dip with the vacuum cleaner or the mitre saw starting up, even on different circuits. The PSSC is something like 800A from memory so nothing too close to the limit.

That rather surprises me with the the loads you mention. As above, it could only happen if their were a VD arising at some 'common' point upstream of the origins of the two circuits concerned. If that VD were arising within the CU, meter tails, meter or cutout, then there would be cause for concern. The only other place is in the distribution network where large start-up currents from things like welders and large items of workshop machinery can result in significant transient VDs in the distribution cables (hence dimming neighbours' lights - which is why DNOs get concerned about such loads) - but I would not expect that to happen noticeably with a vacuum cleaner or mitre saw motor.

Kind Regards, John

 

[oldbutnotdead]

Nor me, and I think that's because what oldbutnotdead suggested can't possibly be true.

Inadequacy of cable size within the final circuit supplying a particular load can result is problems (for that circuit/load) of VD during high start-up currents. However, to affect (result in a VD in) other final circuits (like lighting) would require a VD upstream of the origin of the final circuit (i.e. somewhere common to both circuits)
That rather surprises me with the the loads you mention. As above, it could only happen if their were a VD arising at some 'common' point upstream of the origins of the two circuits concerned. If that VD were arising within the CU, meter tails, meter or cutout, then there would be cause for concern. The only other place is in the distribution network where large start-up currents from things like welders and large items of workshop machinery can result in significant transient VDs in the distribution cables (hence dimming neighbours' lights - which is why DNOs get concerned about such loads) - but I would not expect that to happen noticeably with a vacuum cleaner or mitre saw motor.

Kind Regards, John

I was more referring to the garage setup- in my old shed (2.5mm supply) the fluorescent lights would dip and flicker when I was welding. New shed (6mm supply) they don't.

In my old kitchen the lights would dip a bit when I switched the (electric) oven on but they were downlights on a dimmer so put it down to that and didn't really worry about it for the reasons above- could have put a volt monitor on but never bothered. Not having anything like that happening in the House of Pain with mitre saws etc (but all the lights here are LED so probably far less sensitive to that sort of thing? )

 

[chivers67]

Thanks to everyone for your thoughts. To summarise:

- My installation is a bit of a poopshow
- I should probably use an RCD if I want to use a table saw
- It's not really possible to tell if the installation is up to the mark to use both a table saw & dust extractor in the garage
- I need to get an electrician out to answer that and most likely do some remedial work

To be honest given your views of what I've shown you (which is the handy work of three different electricians), I'm not sure if I can even trust anyone I call out but I guess I'll have to take that risk if I want to realise my dream of accidentally lopping my tits off with a table saw

I think your partner would be happier if it was just your bra .

Do you know the power out put of the Table Saw and dust extractor combined? I can't imagine they'd overload the circuit though.

 

[JohnW2]

I was more referring to the garage setup- in my old shed (2.5mm supply) the fluorescent lights would dip and flicker when I was welding.

Fair enough, and that is exactly what one would expect iof the garage lights and welder were supplied through the same cable. However, as I implied, if the lights and welder had been on different circuits then increasing the size of the cable feeding the welder would not have changed anything - in fact, things might have got slightly worse, since the start-up current of the welder would then be a little higher!

In my old kitchen the lights would dip a bit when I switched the (electric) oven on but they were downlights on a dimmer so put it down to that and didn't really worry about it for the reasons above ...

I have to say that unless the downlights were supplied from the cooker circuit (or whatever circuit was supplying the oven), I would not really expect that as a noticeable phenomenon - for reason's I've explained.

Kind Regards, John

 

[Abby6006]

I think your partner would be happier if it was just your bra .

Do you know the power out put of the Table Saw and dust extractor combined? I can't imagine they'd overload the circuit though.

Ha true! I'd love a SawStop but it doesn't seem possible to get one here.

3kW roughly - 1800W for the table saw and 1200W for the dust extractor, plus the LED light battens whatever they are, not more than 100W I'd imagine.

Not too far off a kettle really?

 

[oldbutnotdead]

Ha true! I'd love a SawStop but it doesn't seem possible to get one here.

3kW roughly - 1800W for the table saw and 1200W for the dust extractor, plus the LED light battens whatever they are, not more than 100W I'd imagine.

Not too far off a kettle really?

Festool seem to do them (Google being v sluggish at the mo) but their kit (although very lovely) is priced for commercial users who will be running it to make money all day. Mind, if you've budgeted for a SawStop you might be OK

Re the other stuff- if you've got the saw & extractor already and are itching to try them out then you'll be best running the extractor continuously rather than firing it up with the saw. LEDS yeah 58w each usually for a 5', about the same as a fluorescent. But do get someone out to have a look at the installation fairly soon....

 

[JohnW2]

LEDS yeah 58w each usually for a 5', about the same as a fluorescent.

LED tubes are generally of about half the power of same-length fluorescents (hence generally in the range 24W-30W) but theoretically give out about half as much light (hence about the same light/watt). However, as I've often said, whenever I changed a fluorescent tube to a (about half power) LED tube, I haven't really usually any reduction in illumination.

Kind Regards, John

 

[big-all]

Ha true! I'd love a SawStop but it doesn't seem possible to get one here.

3kW roughly - 1800W for the table saw and 1200W for the dust extractor, plus the LED light battens whatever they are, not more than 100W I'd imagine.

Not too far off a kettle really?

you could still loose a finger or two with a saw stop so they should show you a dry sausage swung hard to replicate an actual accident rather than a wet sausage moving at 5mm a min until the wet removed from the skin triggers the stop action

 

[Abby6006]

you could still loose a finger or two with a saw stop so they should show you a dry sausage swung hard to replicate an actual accident rather than a wet sausage moving at 5mm a min until the wet removed from the skin triggers the stop action

If I ever find a demo somewhere I'll be sure to bring my wet sausages with me

 

[Abby6006]

Festool seem to do them (Google being v sluggish at the mo) but their kit (although very lovely) is priced for commercial users who will be running it to make money all day. Mind, if you've budgeted for a SawStop you might be OK

I remember Festool buying them and hoping they'd start bringing them to the UK, seems they have started integrating the technology but of course makes things pricey. It's pie in the sky holy grail table saw territory for me really, I wouldn't have the skills to take advantage of it (yet!). I do like my fingers though.

 

[oldbutnotdead]

LED tubes are generally of about half the power of same-length fluorescents (hence generally in the range 24W-30W) but theoretically give out about half as much light (hence about the same light/watt). However, as I've often said, whenever I changed a fluorescent tube to a (about half power) LED tube, I haven't really usually any reduction in illumination.

Kind Regards, John

I sit corrected- saw some LED replacement tubes in Aldi or Lidl a while ago- was interested in them (to use in the van when running on inverter) but went off the idea when I checked the power (naughtily they quoted current required rather than W so I had to do sums). I've recently acquired (that dent in the box where it fell off the van won't hurt anyone) a purpose-made LED 5' batten- not looked at the power requirements yet