Forums > General Discussion   Shooting the breeze...

Help Me Electrical Experts!

Reply
Created by Shifu > 9 months ago, 21 Jul 2016
Shifu
QLD, 1960 posts
21 Jul 2016 10:38PM
Thumbs Up

I'm carefully studying my options for buying a new Table Saw (not ALDI this time). Some have 10 amp plugs, some have 15 AMP plugs, and some require three phase power

I understand that 10 amp plugged machine will only require single phase power, and this is the simplest option though overall grunt will be limited.

But I am not sure about 15 amp. Does 15 amp indicate three phase power is needed, or is it just 15 amp single phase, requiring a dedicated thicker wire circuit from the meter box, special socket, and ultimately not too expensive to set up.

I believe three-phase is a whole other kettle of fish requiring some expensive wiring adjustments to your power supply.

So have I got this right?

Cassa
WA, 1305 posts
21 Jul 2016 8:50PM
Thumbs Up

I think so .
I changed the female end of a short extension cord so I could plug in my mig welder to a 15 amp . Built a steel framed house and have gone through 2 large coils of wire in the past 4 yrs and have had no trip outs or problems.
Probably illegal to do so , but it wors fine.

cauncy
WA, 8407 posts
21 Jul 2016 9:03PM
Thumbs Up

What are you cutting ?

Mark _australia
WA, 22414 posts
21 Jul 2016 9:14PM
Thumbs Up

Yes you are right, 3 phase is an expensive connection. 15A is just a different powerpoint with higher rating obviously but still normal mains power single phase. Most houses used to have a 15A point somewhere outside or in garage.

Interesting as I am looking at a new compressor - and the ones I need are just into the 3hp range and thus have a 15A plug fitted. But my poxy rental house does not have any 15A plugs (seriously why not just one in the garage??? grrrr)

I ran arc welders for years off 10A even though they have a 15A plug, no problems.
So sorry to hijack but I'd be interested to know also

And if I do need a 15A one can the sparky just piggy back off the aircon wiring (it uses 18A) to run to the powerpoint, so as to do it cheaply? Rather than running from the board to the garage and putting in a new breaker for 15A powerpoint etc etc...



sn
WA, 2775 posts
21 Jul 2016 9:25PM
Thumbs Up

A 15amp saw should be plenty powerful for a home workshop / 3 phase is most likely getting carried away.

10 amp circuits almost always have several power outlets per circuit, which is fine as long as you are not running several appliances that might draw heaps of power at the same time.

In my experience, having a standard 10 amp circuit being loaded up with my small welder, fridge, tuckerbox freezer, missus's hair drier and a toaster all running at the same time will result in dodgier than normal welds.

===============================

A 15 amp circuit is a dedicated single outlet, single phase circuit with heavier duty wire to carry the load.

These sockets and plugs have a larger earth pin so the 15 amp plug cannot be inserted into a 10 amp supply, but a 10 amp plug will fit into a 15 amp socket.

===============================

3 phase supply [iirc] starts at 20 amp, commonly comes in higher ratings, but can be considered pretty much for either seriously dedicated hobbyists or industrial type stuff.
3 phase power will be expensive to install!



Ideally, for home workshop stuff, a couple of 15amp sockets [1 x each side of the shed for better access?] and a bunch of 10 amp sockets spread around is pretty damn handy and should be more than enough.

I had a 15 amp socket put in for a A/C unit which is mounted high on our verandah wall - I can unplug the A/C and run the welder from there if needed.
On the other side of the house, the new hot water system required a power point for it's igniter and fan, so it has been given a 15amp socket as well.


stephen

sn
WA, 2775 posts
21 Jul 2016 9:29PM
Thumbs Up

Select to expand quote
Mark _australia said..

And if I do need a 15A one can the sparky just piggy back off the aircon wiring (it uses 18A) to run to the powerpoint, so as to do it cheaply? Rather than running from the board to the garage and putting in a new breaker for 15A powerpoint etc etc...




is your A/C hard wired - or plug-in?

I just unplug our A/C and use it's 15amp socket for my welder [until the sandwichmaker finds out]


stephen

decrepit
WA, 12161 posts
21 Jul 2016 9:30PM
Thumbs Up

I'm not sure but I think a 15A outlet needs to be the only one connected to a 15A fuse/breaker, at least that's the way this house is wired. But I guess if you have two devices going at once you'll just blow the fuse.

Three phase could require another connection from the mains which could cost buckets, but if there's already 3 phase to the house should be about the same as wiring a 15A outlet in.

sn
WA, 2775 posts
21 Jul 2016 9:41PM
Thumbs Up

Select to expand quote
decrepit said..
I'm not sure but I think a 15A outlet needs to be the only one connected to a 15A fuse/breaker,

Three phase could require another connection from the mains which could cost buckets, but if there's already 3 phase to the house should be about the same as wiring a 15A outlet in.


15amp is a dedicated circuit - only 1 x socket allowed [so my tame electrickery bloke told me]

3 phase requires 4 [heavier] cables, 3 x active and a neutral.

3 phase also requires different sockets, plugs and circuit breakers which cost loads more than the 15 or 10amp types.
3 phase would also need to be run direct from the meter box, [same principal as 15 amp] you cannot tap into an existing circuit


stephen

Tequila !
WA, 931 posts
22 Jul 2016 3:03AM
Thumbs Up

15A can be reticulated and distributed among a few GPO's, however the whole feed and fusing, RCD has to be appropriately sized.

I had a 15A dedicated GPO (one only) wired to my garage. Called a sparkie and got it done for 300AUD aprox 5 years ago.
In the price included the extra (new) RCD in the meter box, and a whole new 30 meter long aprox wire to the GPO location in my garage.

I use it mostly for welding, but mainly a 3HP compressor.

Are you doing a lot of sawing? If not a 10A rated saw shall do the job.

I also have 3 Phase in my meter, only use for it is the bore pump. A lot of new houses don't have 3 phase wired to them as normal (smaller blocks don't need large bore pumps and so forth).

Do your research prior spending money with a sparkie. Having a license doesn't mean the job he does will be compliant or top notch. I have seem a lot of shoddy electrical work done by licensed electricians. It helps a lot when the client knows a bit.
Usually they are very lazy to route wires properly in roof cavities (or the use of conduits in the roof of in the walls).

They just pretty much lay feed wire above roof trusses (timber or steel), above insulating material, in no proper fashion and most of the times it looks like a untangled mess like the cables from a kitesurfer bar from time to time.

Beaglebuddy
1595 posts
22 Jul 2016 4:04AM
Thumbs Up

The amps available will probably determine the size of the saw blade. That's the case in the US at least where our homes are equipped with 15 or 20 amp circuits. Three phase will need to come all the way from the power pole or underground in the road, it's for industrial uses and probably not even available in a residential neighborhood so I would just forget about that.



saltiest1
NSW, 2496 posts
22 Jul 2016 7:45AM
Thumbs Up

Select to expand quote
Beaglebuddy said...
The amps available will probably determine the size of the saw blade. That's the case in the US at least where our homes are equipped with 15 or 20 amp circuits. Three phase will need to come all the way from the power pole or underground in the road, it's for industrial uses and probably not even available in a residential neighborhood so I would just forget about that.






You might be surprised. Heaps if houses I do work on have 3 phase for water heaters. Wouldn't be hard to run a cable from the box to the required outlet.

Beaglebuddy
1595 posts
22 Jul 2016 5:59AM
Thumbs Up

Well if that's the case I personally like the most powerful tablesaw I can get for ripping tall pieces. It probably will come down to what size saw is needed and the budget.

crustysailor
VIC, 870 posts
22 Jul 2016 10:05AM
Thumbs Up

shifu you can also buy a 10A to 15A adaptor, for around $60-$80.
I bought one from Total tools for my 15A welder, but I think Bunnings have them also.

You still won't get 15A obviously, but it includes a resettable switch that will trip if you draw more than the 10A circuit can handle, and will help. to save the house going up in some because the wiring can't handle the load.

As said above, it will depend how much other load you have on the circuit running at the same time

myusernam
QLD, 6124 posts
22 Jul 2016 10:17AM
Thumbs Up


i think you are dreaming if you think you need it. A good blade and go slow.

SP
10979 posts
22 Jul 2016 9:32AM
Thumbs Up

Plenty of good info and some bad above but If memory serves...

Their will be no effect on the output power of the appliance.

The normal power socket will be rated 20 amp, the Circuit breaker will be 20 AMP ( maybe 16, mixed circuit) . So you won't burn them up or anything.

20Amp is the Australian standard. They will not be 10..

The issue is the current draw and tripping the breaker. This is only an issue if the circuit is already loaded say a fridge and then when you turn on the next item and it exceeds 20amp or has a resistance loss before coming back to the breaker.

If it trips the breaker try another socket. or unplug stuff from the circuit.

To plug it in an adapter is the go, can be made with a 15amp socket and a 10 amp plug with a bit of extension lead in between.

Solar HW or AC are good if they aren't in use and have an outlet as they won;t have anything else on them.

If the appliance is 3 phase it will have a round earth plug. 3 phase is 415v single is 240volts so they are completely different power and attachment.

Everything else, will have a normal flat sided earth plug and be single phase.


sotired
WA, 598 posts
22 Jul 2016 9:51AM
Thumbs Up

Select to expand quote
Beaglebuddy said..
The amps available will probably determine the size of the saw blade. That's the case in the US at least where our homes are equipped with 15 or 20 amp circuits. Three phase will need to come all the way from the power pole or underground in the road, it's for industrial uses and probably not even available in a residential neighborhood so I would just forget about that.




Over here, in most suburban areas, three phase is available, and they just generally connect each house to a different phase to spread the load. If you require 2 or three phases, you just have the extra fuses, switches, and meters, to suit.

In older houses here they used to have stoves on a different phase to spread the load but now they tend to run a single phase that has more capacity. The lead-ins to the house are single phase or 3 phase, i.e. 2 wires or 4 wires, and if you don't have a need for the extra phases, they don't wire them up past the first fuse.

Don't they have 2-phase circuits in the US to run things like dryers and the like at 220v?

Mark _australia
WA, 22414 posts
22 Jul 2016 10:39AM
Thumbs Up

Select to expand quote
SP said..
Plenty of good info and some bad above but If memory serves...

Their will be no effect on the output power of the appliance.

The normal power socket will be rated 20 amp, the Circuit breaker will be 20 AMP ( maybe 16, mixed circuit) . So you won't burn them up or anything.

20Amp is the Australian standard. They will not be 10..

The issue is the current draw and tripping the breaker. This is only an issue if the circuit is already loaded say a fridge and then when you turn on the next item and it exceeds 20amp or has a resistance loss before coming back to the breaker.

If it trips the breaker try another socket. or unplug stuff from the circuit.

To plug it in an adapter is the go, can be made with a 15amp socket and a 10 amp plug with a bit of extension lead in between.

Solar HW or AC are good if they aren't in use and have an outlet as they won;t have anything else on them.

If the appliance is 3 phase it will have a round earth plug. 3 phase is 415v single is 240volts so they are completely different power and attachment.

Everything else, will have a normal flat sided earth plug and be single phase.




So are you saying it is safe to pull 15A on a 10A plug...... like the thinner wiring won't overheat etc? And the only issue is the breaker?
I am still trying to figure out if I can run a 3hp compressor on 10A plug (BTW Stephen yes the bloody a/c is hardwired so I can't just use that. Shame as the AC is 18.3A)

TheRodder
WA, 319 posts
22 Jul 2016 10:53AM
Thumbs Up

US domestic supply is single phase, 240v, centre tapped. Most circuits are 120v between the centre tap and active, dryers and ovens go across the whole 240v.

Shifu
QLD, 1960 posts
22 Jul 2016 1:08PM
Thumbs Up

Thanks for all this info everyone.

I don't need three phase I just wanted to be sure 15amp wasn't just another way of saying "three phase"

If I can get a 10 amp plugged saw I will be sweet, but it sounds like a 15 amp saw won't be much of a problem.

Reason is I just bought a house with this 6x6 shed. My dream is to equip it with:

Bandsaw,
Tablesaw,
Drill press
Mitre saw
Disc sander
Timber racks
Board repair racks
Storage racks full of fasteners, fittings, paints and resins






There's another one at the front of the house to store all the sailing gear.

I'm going to do heaps of windsurfing, build a little sailing boat, do repairs, and make my own furniture.

Happy days!

Beaglebuddy
1595 posts
22 Jul 2016 1:41PM
Thumbs Up

It really comes down to blade size, I don't know from metric madness but I can assume your table saws are in similar classifications to ours. A 10 inch table saw is standard and portable and plugs into regular wall outlets but it won't rip a 2 x 4.
A 12 inch table saw is generally not portable and requires the same size power outlet as a stove or dryer for example. They are more solid, have more precision, more capable.

crustysailor
VIC, 870 posts
22 Jul 2016 3:54PM
Thumbs Up

given that's the size of your shed, I'd guess it just have a few normal 10A powerpoints when it was built, if that?

Most of the tools you mentioned would only need 10A anyhow, so why not just keep it simple.

Unless you wanted to do it properly and get a new 15A supply put on back to the switchboard, you are still going to end up doing all that you listed with the 10A's that's currently there.

It's true you could make an adapter lead up as described pretty easily, or others might grind down the 15A earth plug to fit your existing 10A GPO, you decide if either is a good idea.

Or you just buy the commercial product that does this for you, and includes a resettable circuit breaker for the times when the current draw approaches the 10A limit.

Plenty of fun to be had in that shed.

lee1972
QLD, 921 posts
22 Jul 2016 4:18PM
Thumbs Up

Haven't read all the other posts but you will require a dedicated circuit from your mains board. As its all feeding an outlet it will have to be protected with a safety switch. 2

el tubo
NSW, 113 posts
22 Jul 2016 6:23PM
Thumbs Up

The easy solution would be to go to the electrical wholesaler and buy a 15 amp GPO.
Isolate your circuit and then swap it over.
Normal GPO's are rated at 10 Amp but they are protected by a 20 Amp RCD.
The reasoning behind Circuit Breaker/RCD current rating is to protect the cable and prevent it from over heating.

But this depends if the GPO is close enough to your work bench.
If it is too far away then Cassa's idea is the best.

Buy an extension lead and put a female 15A 3 pin plug on the end of it.
Or buy a 15A extension lead and put a 10A male 3 pin plug on the end of it.

The circuit will be protected by a 20A breaker so you should have no problem if you turn off your heater first.

The only difference between a 10 Amp GPO and a 15 Amp GPO is the size of the earth pin.

Piv
WA, 372 posts
22 Jul 2016 5:01PM
Thumbs Up

Nice looking shed shifu. It's a bonus having two with one nice and clean and the other dirty. Go to hare and Forbes and check out their machines. You can do all you want I think with 10a machines. But if you want good industrial rated stationary machines they will be 15a or three phase. Having three phase opens up a second hand world of ex industrial machines that most people can't power. But a 6x6m shed fills up quick. If you are just starting I would get a triton workbench and the best hand held circular saw and 1/2" router you can buy. My jap makitas I bought 30 years ago are still great. Not sure about the Chinese makitas, a couple of drills and grinders ive had look the same but haven't lasted. There are some nice combo machines around but you have to pay a lot to get better than a triton. If you are going to run extra power, get three phase run to the shed. Then you can hang heaps off it.

Harrow
NSW, 4521 posts
22 Jul 2016 7:58PM
Thumbs Up

I run 15A equipment off 10A power points. I just made up a short extension lead that has a 15A socket on the end. Comes in handy.

Remember, you can easily end up with well over 10A on a normal house circuit just by plugging in a couple of appliances. A heater uses 10A, a kettle uses 10A. So you can have 20A with just those two plugged into a double power point. So I figure no problem plugging in a 15A bit of equipment, as long as I make sure there are no other loads on that circuit at the same time. Besides, a table saw is only cutting a small percentage of the time, so the average current would probably be a lot less than having a heater running continuously anyway.

Of course, I could be totally wrong, but haven't started a fire yet.

shoodbegood
VIC, 873 posts
22 Jul 2016 8:23PM
Thumbs Up

Depends on what you want to build
Maybe a Makita 9 1/4 under a Triton work bench would do the job, probably rip 70-75mm?
Remember the old saying, "sharp boys have sharp tools", its all about the blade!

sn
WA, 2775 posts
22 Jul 2016 6:56PM
Thumbs Up

Select to expand quote
Mark _australia said..


So are you saying it is safe to pull 15A on a 10A plug...... like the thinner wiring won't overheat etc?


The way I read it, these adaptors will allow you to physically plug a 15amp power-tool into a 10amp socket.

But....the supplied power is governed to a maximum of 10amps.

Sounds cool to me



stephen

cauncy
WA, 8407 posts
22 Jul 2016 7:00PM
Thumbs Up

What on EARTH do you need 3 phase for,
Some POSITIVE replying here

Shifu
QLD, 1960 posts
22 Jul 2016 9:08PM
Thumbs Up

I never said I wanted three phase. I'm just sorting out the nomenclature so I know what I am doing when I buy something.

Shifu
QLD, 1960 posts
22 Jul 2016 9:09PM
Thumbs Up

Select to expand quote
lee1972 said...
Haven't read all the other posts but you will require a dedicated circuit from your mains board. As its all feeding an outlet it will have to be protected with a safety switch. 2


You're my go to sparky Lee

busterwa
3777 posts
22 Jul 2016 7:42PM
Thumbs Up

Shed is small ;-) 15 amp is single phase standard and you probably got your house gpo outlets running a 15 amp circuit breaker with a 2.5 core. The idea is the circuit break will trip @ 15 amp before the wire melts starting fires .
Seems like your trying to run commercial equipment Run 3 phase.
If you jump 15 amp single phase into a circuit already with high usage It will trip out or every time your saw startsYour house ligt will dim and stuff like tv and stuff will be fried with the power flutuction.
lee1972 would be correct.



Subscribe
Reply

Forums > General Discussion   Shooting the breeze...


"Help Me Electrical Experts!" started by Shifu