16 Amp supply for bandsaw

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Spectric

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Yes the good old 110 site extension leads, left to their own devices you can end up with a real mess, people just plug an extension into an extension and eventually reach where they want to be but just no power left. I have followed these trails around sites and they can be amazing, up and down floors and even doubling back when if a little thought had been applied they would have realised there were several distribution boxes on every floor.
 

JobandKnock

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That's a regular thing to check when one of the lads rings and tells me the compressor isn't running or their router won't run at full speed. The biggest offenders for cutting into other people's power supplies are steel fabricators and paviors , I find, who tend to have big 2.2kW angle grinders that hog all the voltage.
 

Peri

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Not knowing what you are cutting, but let's assume sheet goods then rather than the table saw have you thought about a tracksaw! With a couple of tressles it will give you a Portable solution for less cost.

Unfortunately, sheet goods are one of the things I cut least. I buy timber 'sawn', and also use a lot of reclaimed stuff that needs breaking down. My Fisher-Price 8" saw (ok, it's a Draper) is fine for smaller stuff, but trying to cut a 2.5" thick piece of maple isn't fun, or this 4' chunk of oak (that I haven't attempted yet!)

20210808_135745.jpg

The smallest Itech is 122kg - 19 stone - that's a fair amount to be moving around.

Thanks for the wise words folks :)
 

Sideways

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One observation. Corded site tools are normally 110V.
Very crudely, they are designed for less than half the Voltage of the 240V ac mains and draw more than double the current for the same power (power = current x voltage).
Double the current means double the volt drop in the extension cable if you were comparing a 110v and 240v tool on the same gauge extension. This makes a big hit on a tool that is already more sensitive to voltage because it only uses half as much to start with.
So yes, high power 110V site tools need thicker extension cables than 240V domestic and long runs on building sites just make that even more essential.

The up side: as 110V is dropping out of fashion on building sites, unwanted 110V extensions are great repurposed for 240V with the proper blue CEE form connectors. They are heavy duty, thick, usually rated safe for voltages well above 240V (but do check the markings printed on the sheath). The yellow or orange sheath is just a high vis colour, the wiring regs don't care what colour the outer insulation is on a cable, only the inners and the plug / socket so that you can't connect to the wrong voltage. It's perfectly OK to fit blue plugs on a yellow coloured flex.
 

JobandKnock

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The up side: as 110V is dropping out of fashion on building sites....
I've lost count of the number of times I've heard that in recent years. It's only really disappearing on domestic sites such as tract housing where operatives tend to use cordless kit and where 110 volt was never that well supported, based on the number of guys who used to have their own petrol gennyies. On high density mainstream builds, such as in city centres, 110 volt is still very much alive and well partly because there is still a dearth of the cordless equipment you need to do so many tasks (for example who makes a cordless heat gun and how many batteries does it take to run a 9in grinder for a decent while?). I agree that 110 volt cords can be repurposed, but 110 volt isn't dead yet, and won't be for many years to come
 

Spectric

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(power = current x voltage).
Only in a Dc circuit, once you have Ac then it is a different ball game because you now have both real and reactive power. Any reactive load such as a motor with both inductance and capacitance will deliver zero power but still draw current and cause a voltage drop. Unlike real power measured in Watts, reactive power is measured in volts-Amps-Reactive or VAR and symbol Q. So true power becomes volts squared / resistance whilst reactive power becomes volts squared / reactance . Essentially this is where the term power factor comes into play, also shown as Cos Theta which is the ratio of real power that produces power to apparent power or energy used that is not doing useful work.

I think 110 volts will be around for a long time yet, it is a safer system in harsh enviroments and limits any potential shock to 55 volts to ground. Tools such as cement mixers, heavy grinders or concrete pokers will run all day compared to needing an endless supply of batteries and if you look at a 110 site distribution boards they have 32 amp outlets as well as 16 amp outlets to deliver the higher capacity either to those tools that need it or to overcome cable distance. My 9 inch grinder requires a 32 amp 110 transformer. Also I believe that the 110 volt tools last better than there 230 volt cousins, I have never cremated a 110 volt motor but have several 230 volt tools over the years and maybe the manufacturer makes these site tools more durable simply because they know how they will be expected to work.
 

Phil Pascoe

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Inspector

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Spectric would your 110V tools be the same as those sold here or different than ours? Cord plugs not included. 😉 Those I know will be different. I have never seen ours over 15A and my home has 15A for most circuits except in the garage and shop plugs that are 20A. 220V portable tools are pretty rare here too. Thanks.

Pete
 

Phil Pascoe

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Also I believe that the 110 volt tools last better than there 230 volt cousins, I have never cremated a 110 volt motor but have several 230 volt tools over the years and maybe the manufacturer makes these site tools more durable simply because they know how they will be expected to work.

I spoke to a chap who's spent a couple of decades using and selling second hand power tools - he said exactly the same.
 

Sideways

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Interesting to get your feedback from site guys. I'm retired now so not seeing it first hand for the last few years.
Totally agree about the high current / long run time tools, my own two most recent buys have been a 1800W cordless angle grinder and a 1750W corded. Both great, but the cordless is no good for a 2 hour long task.

Spectric - you got me. I skipped the subtleties for simplicity. Both real and reactive current do need to be taken into account in cable sizing calcs but I think we'd both agree that 110V does need those thicker extensions just as J&k described.

On the durability point, I think those tools available in 110V may well be tougher in either voltage. I've owned (by accident) identical blue Bosch Pro SDS drills in both 110 and 240 versions. Build, weight, handling etc were equally good.
Maybe 110v kit spends more of it's life connected to undersized or overloaded extensions and so the motors are not being driven to their rated power :)
 
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Spectric

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Spectric would your 110V tools be the same as those sold here or different than ours?
I believe your 110 volt supply is 0 to 110 volt Ac at 60Hz wheras our 110 is 55 - 0 - 55 with the centre tap earthed and at 50Hz.

Both real and reactive current do need to be taken into account in cable sizing calcs

When undertaking a design your cables need to be capable of supplying the total current without exceeding the allowable voltage drop, if the reactive part could be ignored then there would be no need to have power factor correction systems. The actual power in Kw is voltage times current times cos Ø and if three phase multiply by 1.732. In this equation the reactive power is dealt with by using the power factor.
When power factor is 1, apparent power = true power and there is no reactive power and therefore we can effectively ignore the power factor and it would be a purely resistive circuit with both voltage and current in phase.
 

JobandKnock

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OK, Phil, point taken - but is that really going to be good enough to allow a roofer to lay an entire Sarnafil roof? I doubt it. I've worked with guys covering balcony openings that I'd formed where they were running a 2kW gun all day long (the guns need to be run continuously otherwise the heater coils will fail prematurely, apparently). That gun is simply never going to be able to do that without a large quantity of batteries - all of which have to be humped up to the roof space every day (think 5 and 6 storey high Victorian buildings and you'll see why that is a pain). Similarly there is now a 40 volt 235mm cordless rip saw from Makita which theoretically has the capacity to cut 85mm thick joists and 170mm thick beams in 2-passes, but I'm dubious that it would have enough duration when compared to my Hilti WSC-85 and I wouldn't want to try cutting out a multi-skinned floor containing nails, loose iron tongues, etc. That;s a job which strains even a heavy corded saw. My feeling is that cordless tools still can't do everything, especially the long duration power intensive stuff
 

JobandKnock

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...would your 110V tools be the same as those sold here or different than ours? Cord plugs not included. 😉 Those I know will be different. I have never seen ours over 15A and my home has 15A for most circuits except in the garage and shop plugs that are 20A. 220V portable tools are pretty rare here too. Thanks.
Most 110 volt tools here are limited to 16A and come with a BS.4343 plug. Some tools are rated above that and come with a 32A plug (e.g. my portable compressor). I've had no problems running US-sourced 110 volt tools off UK-style 55-0-55 volt centre tapped transformers. Maybe I've just been lucky
 

Spectric

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I've had no problems running US-sourced 110 volt tools off UK-style 55-0-55 volt centre tapped transformers.
I think that the main issue would be the frequency, 60Hz and not 50Hz which might give different motor speeds and cause the motor to run hotter, nice on a cold day. I would also question what type of insulation class are American tools, more than likely double insulated because of the 110 volts and from what I have seen are only two pin.
 

JobandKnock

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I thought the frequency only affected induction motors. Most power tools have universal motors, don't they?
 

IanB

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The expertise on this forum never ceases to amaze, thanks to all the contributors (although much of it goes over my head I'm afraid!)

Hi Steve
I stuck with the 2 metre extension lead for a week or two but then realised that I had a similarly constructed lead for our caravan that is about 30 centimetres long so I used that instead as there is less lead to get in the way. The bandsaw has had constant use since it arrived and there hasn't been a single problem with this arrangement. For what it is worth my whole workshop works off a spur into a household ring main and I know that I should alter this but my only problem has for some reason come from a small dust extractor that is used infrequently. The mini lead from a caravan supplies shop is a cheap way to test whether this will work for you. Best of luck.
Peter

@Bodger7, out of curiosity is there any reason why you don't just fit a 13A plug on the bandsaw lead, or is it just that you need the extra 30cm length?
 
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