Do I really need a 15 AMP plug

[Damienol]

Hi WWF

I am looking to purchase the Hafco BP-430 bandsaw. It has. 2hp motor and comes with a 15amp plug. I forgot to look at the plate on the motor when I was in the shop so don't know the exact current it draws. However using the following
Electrical Motor Calculator (http://www.engineeringtoolbox.com/electrical-motor-calculator-d_832.html)

and using default values for efficiency and power factor I think I t needs about 6 amps. Thus a 10amp plug should be fine.


i also have the Hafco Dust extractor which also has a 2hp motor and only a 10amp plug.


Anyone see any major flaws in my logic?

[artme]

Get yourself a 15amp circuit and plug. That way no problems.:)

[BobL]

It looks like they might have been a bit sloppy with the cutting and pasting from larger machines on the website.

[Damienol]

It looks like they might have been a bit sloppy with the cutting and pasting from larger machines on the website.

Thanks for the reply Bob.

I actually eyeballed the machine and it does actually have a 15A plug end

[doug3030]

i also have the Hafco Dust extractor which also has a 2hp motor and only a 10amp plug.


Anyone see any major flaws in my logic?

Hi again Damienol,

I noticed that too on H&F website when I was looking at that saw on your behalf for another post. I almost mentioned in my reply that I did not think it needed a 15 amp plug as it is only 2hp motor and single phase.

I would be cautious, however, of running the 2hp saw and the 2hp dusty off the same circuit. Do not under any circumstances start them both on the same 10 amp circuit at the same time as start-up current is much higher than running current. Use common sense, if the circuit breaker trips more than once, try accessing another circuit for each machine even if it means running an extention lead from another circuit in the house.

In any case, if you follow the following advice from BobL in another thread, you cant go wrong


The 30A circuit breaker (CB) will be either a Stove/Oven or Aircon or HWS.
The 15A CBs protect the standard 10 A outlets inside the house, (usually 20 or 25 A CBs are used to protect 15A outlets and standard installation is one outlet per breaker).
The 15A designation is nominal continuous value but it can handle slightly higher currents for a brief period.

FIRST THE DISCLAIMER ** If you are not confident of doing the following call in a sparky to tell you what is going on **

Since there is no CBB in the shed and you cannot identify a specific shed CB in the house CBB, you need to determine which of those CBs in the house CBB, controls the shed.
Do this by connecting an appliance (something like a desk lamp is the safest thing to use) to an outlet in the shed and turning it on and then turning the House CBs of-on systematically. Then you need to work out if that CB is for the shed alone, or if it connected to one of the house circuits by testing for power using the desk lamp on all the house outlets. If none of the house circuits are affected then that CB is for the shed alone.

If that CB is connected to one of the house circuits then you will need to check what appliances are running on the circuit. if they are all small appliances like power adapters then you can pretty much ignore these. However if they are high current continuous devices appliances like dryers or air conditioners then you need to take these into account

Assuming that you can identify a 15A CB that is dedicated to the shed then . . . .
If the Ledacraft is a 1.5HP that means it will draw ~4A free running and ~6A under working load.
This pretty much restricts you to a 2HP (~6A) since a 3HP draws about 10 A which when added to the saw will send you over the 15A limit .
A 3HP unit requires a 15A GPO and a dedicated 20-25A CB because the start up currents can be much higher than 15A which will trip a 15A CB.

If the line to the shed is part of one of the house circuits then the currents drawn by any large appliances in the house that use the same circuit should be included in the calculation.

The other thing to note is that it is not just a question of changing the CBs in the house CBB. The other limit to total current is the wire diameter.
The line running to the shed can probably only cope with a continuous max of 10 A so swapping the 15A CB on that circuit for a 20A could cause overheating on that line and lead to a fire.

Either way it seems if you want to run a 3 HP or greater DC you would need to upgrade your connection to the shed.

[cava]

Typically, I like pushing the limits. However, in this case, if it came with a 15 AMP plug and was electrically approved with it - do not alter it. To do so will definitely void your insurance.

As an aside, you could contact the electrical approval authority, to verify what rating of plug and lead can be used with the bandsaw on the approval certificate. If it was approved with an alternate 10 AMP plug, then if you wished, change it.

[Wrongwayfirst]

Hi again Damienol,

even if it means running an extention lead from another circuit in the house.


Running an extension lead from another circuit in the house will probably mean a drop in voltage and will lead to the premature death of whatever is plugged in.

Start Amps are often quoted as 3 to 5 times the run Amps, not accurate but a good guide, possibly 30 Amps on that circuit. The saw manufacturer or reseller should be able to answer why it has a 15 Amp plug. However it is generally 10 Amp plug on 2 hp and 15 Amp on 3 hp. If all else fails call a sparky for a quote on a 15Amp circuit, quotes are free and may come with a solution.

[Damienol]

Thanks Doug

I have already experienced a tripped circuit when firing up my shopvac while the Dusty was booting up. Timing is key.

The man cave is wired with 4mm 2CE so significantly larger then normal house wiring so no probs there with overheating. The old man is a sparky so might ask him if it worth changing the CB

The old man has also suggested that if worst comes to fruition he can installed a 15Amp GPO in the CB box and I will just have to run an extension lead to the bandsaw every time I need to use it. Not ideal however significantly more palatable then forking out $1000 plus to run another circuit to the man cave.

[Damienol]

Thanks for your response Wrongwayfirst

Re the extension lead comment, I have 250v to the house so any drop in voltage incurred through the use of an extension lead should be palatable

[doug3030]

Thanks for your response Wrongwayfirst

Re the extension lead comment, I have 250v to the house so any drop in voltage incurred through the use of an extension lead should be palatable

And I am sure that "the old man" will ensure that you are using a properly approved 15 amp lead and hopefully it will be no longer than 30 metres so all would be good.:2tsup:

[rustynail]

A shed without a 15amp socket is not a real shed.

[RETIRED]

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[Damienol]

A shed without a 15amp socket is not a real shed.

Still sticking with the line rustynail?

279185279186279187279188

[BobL]

Thanks for your response Wrongwayfirst

Re the extension lead comment, I have 250v to the house so any drop in voltage incurred through the use of an extension lead should be palatable

Yikes 250V - have you actually measured it?
We routinely get 244-245 but don recall seeing a 250 since the 1980s around here.
A rumour I heard was the state supplier recently cranked up the voltage to put back pressure on the home photovoltaic systems?

[nrb]

Yikes 250V - have you actually measured it?
We routinely get 244-245 but don recall seeing a 250 since the 1980s around here.
A rumour I heard was the state supplier recently cranked up the voltage to put back pressure on the home photovoltaic systems?

Can you please explain a bit more about this,thanks

Back pressure I mean??

[BobL]

A shed without a 15amp socket is not a real shed.

Some might well say that about "3-Phase"

[rustynail]

Goes without saying:D

[Damienol]

Hi Bob,

i last measures about a year ago. Might stick my metre in a socket tonight and take another look

[fletty]

The safest thing to do is get an electrician in to advise you!
Some important points that haven't been made yet are...

a "15 amp plug" is a mechanical device to ensure that it can only be plugged into a 15amp circuit. It has nothing at all to do with the plugs capacity to the job it is only to make sure that you plug into a 15amp circuit.
calculating the current drawn by a motor is pointless if you only look at the full load current. At the time of starting, and depending on the type of motor, the current drawn can be up to 5 times the full load current
AT THIS POINT IN TIME all Australian networks supply at 240V with a tolerance that can be +3%/-6% (225V to 248V) and the utilities in some states suffer pretty substantial penalties if supply is outside that range BUT......
the standard voltage in Europe is now 230V (and I think subject to +3/-3%, 223V to 236V) and there are a number of utilities and regulators looking at changing our standard to match
So, if you have calculated 6 amps at full load, at start up it COULD be 30amps and, if you start your dust collector at the same time, you can very quickly be drawing 40 amps!

The moral of the story is to get a sparky to look at it for you AND it is always good practice to NOT connect your machine and the dustcollector to the same switch and start at the same time.

fletty

[rod1949]

Have ya got a file?:rolleyes:

[Pat]

Fletty, Sydney is now 230V +/-

[fletty]

Fletty, Sydney is now 230V +/-


... but it's supposed to be a SECRET :roll: ?

fletty

[A Duke]

The voltage will vary at your premises according to the load at various times of day. Just check how long a pot of water takes to boil when every one in the street is cooking and at off peak times.
Regards

[BobL]

Can you please explain a bit more about this,thanks

Back pressure I mean??

The higher the mains V the more energy a Photovoltaic system needs to generate put power back into the grid - this means the electrical authorities can then pay photovoltaic power generates a bit less less for their power.

[BobL]

I have current and voltage meters that I can move around and check what the start up and running currents are on with all my appliances and machines.

The most monitoring I have done are on my table saw, 2HP and 3HP DCs, A 2HP (19") BS, and a bunch of other fans and power tools,
The start up currents I can see on my monitoring gear are only small snapshots of what is going on while the devices start up and in actuality will be even higher than what I describe.

The the highest start up currents the BS and DC show for a brief period are ~35A and 25A respectively.
For both machines it takes about 3 seconds for the current to settle to a free running current of 6 A.
The BS and DC have been connected to the same 10A GPO and a 15A breaker circuit and they run fine.
They also run from an expander board with a 10A breaker without tripping.

Of course other DCs and BS may vary.

[Wrongwayfirst]

Have ya got a file?:rolleyes:
:stirthepot:

[Damienol]

249 volts confirmed

[BobL]

249 volts confirmed

We had that today as well, haven't seen it this high for a while.

[Evanism]

Good discussion. I'm about to get in a sparky to discuss upgrading the shed. I'm popping fuses.

Time to dig out the volt-o-matic and check my peaks.

This place has old wiring, no doubt done on the cheap.

[Damienol]

I had a chat to a Sparky and as the mancave is wired with 4mm instead of the usually 2.5mm I can replace the current 20A CB with a 32A CB


This should keep me out off trouble for a while.

[Vernonv]

Have ya got a file?:rolleyes:Nah, too much effort ... just cut that sucker off. Really, how often does the earth pin actually get used. :)

[BobL]

I had a chat to a Sparky and as the mancave is wired with 4mm instead of the usually 2.5mm I can replace the current 20A CB with a 32A CB
This should keep me out off trouble for a while.

That's a real bonus.

BTW my shed hit 250V this morning.

The effect on appliances designed for 220/230V should not be underestimated. In the 1980s in WA when 250 +/- 10% was our standard power a study on the consumption of incandescent light globes showed a significantly greater replacement rate attributed these higher voltages

[A Duke]

Nah, too much effort ... just cut that sucker off. Really, how often does the earth pin actually get used. :)

And if you do need it you could very likely not live to regret it.

:zap::death:


Regards

[rod1949]

And if you do need it you could very likely not live to regret it.

:zap::death:


Regards

Not if the RCD kicks in:buttkick:

[Glennet]

That's a real bonus.

BTW my shed hit 250V this morning.

The effect on appliances designed for 220/230V should not be underestimated. In the 1980s in WA when 250 +/- 10% was our standard power a study on the consumption of incandescent light globes showed a significantly greater replacement rate attributed these higher voltages

My arc welder (Cigweld Inverter) doesn't work because the voltage in my shed is too high. I have to run it through a long extension lead to drop it down a bit.

[Chris Parks]

Tools use power and especially if you run a biggish dust extractor on top of everything else. Run some big cable to the shed and put a sub board in. Far safer and you know you will not run out of power as things are added.

[Handyjack]

Nah, too much effort ... just cut that sucker off. Really, how often does the earth pin actually get used. :)


And if you do need it you could very likely not live to regret it.

:zap::death:


Regards


Not if the RCD kicks in:buttkick:

RCD may not work without the earth pin. Have seen two core cable cut with power on and not trip RCD.
It could be a fatal mistake to remove the earth pin unless the device is Double Insulated.

And what if the circuit is not fitted with an RCD or the RCD has seized because it has not been activated on a regular basis?

[Timless Timber]

or the RCD has seized because it has not been activated on a regular basis?

Mine will all be OK now, I just ran round the house putting a fork in all the power sockets to make sure the RCDs got a work out! :o

Must put it on the calendar to do it once every 6 months! :D :wink:

Anyone know why my hair looks like Phyllis Diller on a bad hair day? :?

:U

[BobL]

Anyone know why my hair looks like Phyllis Diller on a bad hair day? :?

:U

Wasn't that from the quote from the sparky for the 3 phase installation?

[rod1949]

Mine will all be OK now, I just ran round the house putting a fork in all the power sockets to make sure the RCDs got a work out! :o

Must put it on the calendar to do it once every 6 months! :D :wink:

Anyone know why my hair looks like Phyllis Diller on a bad hair day? :?

:U

Timless that made me :roflmao2::roflmao::rotfl:

[Timless Timber]

I try Rod!

Yeah I'm still suffering Bob, nuther sparky quote today.... he wants $2.5K too.... :rolleyes:

Gunna have to start selling my hairy butt on street corners, at this rate! :o :no:

I dunno - maybe it's just me. :roll: I must be outta touch with contractor rates or summut.

[Damienol]

Eyeballed the unit again today. This times checked the plate on the motor. Turns out it needs exactly 10amps.

15amp plug is going to have to stay

[BobL]

Eyeballed the unit again today. This times checked the plate on the motor. Turns out it needs exactly 10amps.

15amp plug is going to have to stay

If it needs 10A then it most unlikely to be a 2HP motor and should be rated as a 3HP motor.
Someone put a current meter on one of those units, plllllllease.

[Ashore]

No one mentioned the "Y" connection lead yet with the two 10 amp plugs wired to a 15 amp socket :doh:

[Chris Parks]

The Jet 2hp BS has a 10 amp plug and the smoke stays in the wires on that, even down to tripping circuit breakers.

[Damienol]

Picked the secondhand unit up today and it has a 10Amp plug!

A 15Amp plug must a new addition in the last 2 years

[Wrongwayfirst]

Picked the secondhand unit up today and it has a 10Amp plug!

A 15Amp plug must a new addition in the last 2 years
So we can shift this thread to "Much about nothing" ha cracker, glad it's sorted.:U

[Vernonv]

Picked the secondhand unit up today and it has a 10Amp plug!

A 15Amp plug must a new addition in the last 2 years... or a previous owner changed the plug.