Thread: First table saw

Originally Posted by DaveVman

So I've had a closer look at what I have. Everything in the shed is currently on a single circuit that has a 16Amp fuse.
It runs underground to the shed in a galvanized pipe.

The line to the house was replaced a few months ago. However the line from there to the switchboard and the switchboard itself are not up to code. So to get a new line I need a new switchboard. Also I probably need a new line to the connection box.

It's doubtful a new line can be pulled through the old conduit but all the sparkies I got to look at it agreed that an above ground connection would be simple.

They all talked about installing a small switchbox inside the shed beside the light switch.

One pointed out that due to the 16Amp fuse I could probably just get away with running everything I want on the existing line. It depends how much the future table saw actually draws. His point was that he suspected the sustained current draw was a lot less than the rating put on the plates on the machines. Plus the startup surge probably wont be long enough to burn a 16Amp fuse.

One sparky doubted that the 2.2kw dust collector actually draws 2.2kw. He said 'its just an impeller'. I'm not sure about that. Air resistance can be a significant force. Although all these motors possibility draw less than advertised.

My worse case scenario would be while I have lights, fans and dust collector going and the air compressor starts itself while I'm using the table saw.

The question is, would a 16Amp fuse be enough?

I don't know what the air compressor draws. I don't have it on all the time. I could try to remember to run only one of the DC or compressor.

I have another complication though. If I load another 25 Amps of table saw and dust collector. The entire system is probably near its limit. Which is reason 2 why I probably have to replace the main line and main switchboard.

have you seen / read this thread? Table Saw keeps tripping the breaker

From memory, BobL has measured the running current of your typical 2hp dusty and found it is around 9-10 Amps. which would sort of leave enough current to maybe run a 2hp saw -- if you could start it without tripping the fuse / breaker. Also any RCD in the circuit would possibly trip.
with 2 x 2 hp motors, your 16 Amp circuit would be running at around 150% of design capacity. Talk to your sparkie if this is a good idea or even allowed.

Originally Posted by ian

From memory, BobL has measured the running current of your typical 2hp dusty and found it is around 9-10 Amps.

I don't think that's right? Maybe work on 7.5 amps.

My modified 2HP doodles along at approx. 5A

My 2HP dusty used to draw about 4 amps.

Cheers, Dom

My DC which is sitting in its box is rated at 3HP which would translate to about 2.2kw which is 10 amps on single phase. However it sounds like the sparky may have been correct.

The guys with a 2HP machine should likewise be drawing about 1.5kw or 7.5 Amps but I note they're reporting running current of 5amps. I.e. 2/3 the rating.

Probably this assumes that air is flowing freely through the system. A blockage may cause it to ramp up quickly.

No electrician is going to put that down in a written recommendation. In fact he made a point to stress I'd be running at about the limit. This is never recommended with electrical installations.
I was originally an electrical engineer and had limited registration back in the day. I didn't tell the sparky I was trained as an electrical engineer because I haven't worked as one for many long years but he probably guessed as much based on my explanation of my requirements. So he made some comments he probably wouldn't have normally.

He still pointed out that the wire to the switchboard for the entire house is probably not adequate anyway. Which is a massive risk when I thought about it.

However I was an electrical engineer back in the days of dinosaurs. And electricity hasn't changed but I have forgotten just about all of it. As I start talking about it I start to remember things but I'm initially unsure and looking for someone to confirm I'm correct.


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Don’t know about Qld, but in NSW the mains into the house used to have a 100A max rating with a 100A service fuse.. That has now been downgraded to 80A so all new or repaired installations have an 80A service fuse. Apparently that’s the safe limit for the new meters, according to my Supplier.

i made up a measuring cable for my 10A power points and one for my 15A power points so I can measure the start up and running amps on all my appliances in the shed.

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Originally Posted by DaveVman

Probably this assumes that air is flowing freely through the system. A blockage may cause it to ramp up quickly.

If a blockage occures the current draw will fall as the amount of air being moved is reduced.

Max draw occures when there is no restriction whatsoever.

Originally Posted by Bohdan

If a blockage occures the current draw will fall as the amount of air being moved is reduced.

Max draw occures when there is no restriction whatsoever.

So much to learn....

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I was in at SEQ Woodworking supplies the other day and Dave has a new shipment of tables saws in. They have the SEQ brand on them but i was told they come from the same factory as the Carbatec saw. I have a 10 year old Carbatec 10" saw that still runs well and cuts very accurate ( as mentioned before, setup and maintenance are the key) but at $1400 i will be buying an SEQ model as it has a superior fence setup with minute adjustment and the cabinet is enclosed so less mess.

So i'll have a second hand saw for sale in a month or so if anyone is interested.

I have just realised that I over estimated my power consumption requirements.
I read in a review that the Harvey HW110LGE-30has a 15Amp plug. So I had this idea in my head that it could draw up to 15A. But I just looked at the specs and it has a 2.2kw motor. So the most it will draw is 10Amps.

If I had the money I'd buy a SawStop Pro which I note also has a 2.2kw motor.

The circuit to the shed is on a 16Amp fuse.

Unfortunately I bought a 2.2kw dusty. If I had bought a 1.5kw dusty I might just get away with the existing circuit.

If I really had to I suppose I could run the dusty on an extension cord from the house. Although I'm loath to run 10Amps continuously through an extension cord I guess it would be doable. The shed is connected to the house via a carport so always under cover and not that far.

We would also need to be careful we don't have the airconditioning plus the oven and fridge and hot water and my workshop machines all on at the same time. I'm probably close to the limit for the entire switchboard.

So now I'm wondering if I can manage with what I have or if I'm pushing things too far.

Perhaps I should just buy some 16Amp fuse wire and find out the hard way.

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You can buy circuit breakers that plug right in to fuse sockets. In fact, if you are still on fuses, I'd highly recommend you get an electrician out to install a safety switch because you probably don't have one.

Before I had the shed rewired, I powered the shed from the old 16A power circuit for the old half of the house. I put a trip circuit breaker in to replace the wire fuse. With the table saw (2000W) and dust extractor (1500W) running, plus shed lighting it would only trip the breaker if SWMBO switched the heater on in the bathroom.

Duplicate post?

Originally Posted by matt_s

You can buy circuit breakers that plug right in to fuse sockets. In fact, if you are still on fuses, I'd highly recommend you get an electrician out to install a safety switch because you probably don't have one.

There is a saftey switch but the switchboard is not up to code in other respects.

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