Curious Power Issue while using Chain Saw with Extension Cable!

ThisIsWeird

As a standard move, SS, I suggest you sit down with both ext cables - unplugged - and thoroughly check the wiring at each end. Pay partic attention to the state of the cables as they exit the ends of the plugs/sockets.
Do you have a test meter?

Section62

ThisIsWeird said:

sujsuj said:

Jonboy_1984 said:

They said on the second page its a garage socket, my guess is someone installed a pre-loaded consumer unit in the garage, and the unmarked 20A's are not connected to anything.

That is why I am wondering what else is plugged in on the same 16amp circuit.

For More clarity, I tried chain saw directly and with extension in 2 sockets...

1.  Garage socket , remember there is a connection from Garage to the Gate control CAME as well. Game control is always plugged  & ON. When I tried direct  chainsaw in socket it worked and MCB tripped when connected with extension.
2. Conservatory Socket - There was a exercise Vibration machine also  worked from that socket, but tried after removing that machine only. When I tried direct  chainsaw in socket it worked and plug 13A fuse spoiled  when connected with extension.

I may have to try again to see if same results again. Also I have a third extension cable to be tried though it is smaller 10M one.

A 13A fuse blew when you used the socket in the conservatory? 
There is surely something more amiss here? 
'Fuses' are relatively slow- blowing, so I'm struggling to think of what condition - other than a fault with the extension cable - could make this happen.
Yes, two cables are seemingly affected, but I've just had two PV inverters come up with the exact same - and very unusual - fault within minutes of eachother. That blew my mind, nevermind anything else.

Motor starting currents can be mind blowingly high. It isn't clear the type of motor in this chainsaw, but as an example, an induction motor in locked rotor condition could draw up to 10 times the nominal running current.  If you do the voltage drop calculation using those levels of current and a long length of cable, then consider the effect of low volts on current draw for a large motor in locked rotor/startup, then it isn't difficult to figure it out.

For some time we had problems running equipment (welders and compressors, not chainsaws) using 13A extension leads, even though the equipment was theoretically capable of running on a 13A plug.  One compressor was guaranteed to blow the 13A plug top fuse when it was started 'cold' in the winter, unless it was first warmed up with a fan heater.

In the end we swapped to DIYed extension leads using 16A plugs and trailing sockets and 2.5mm (in one case 4mm) rough service cable.  Each of the outbuildings has at least one 16A socket on a C16 breaker, and each outbuilding has a dedicated 4mm SWA supply configured as a sub-main.

The problems went away.

This isn't a solution I'd recommend, because you need to know what you are doing, and the cost of this stuff is considerable.  It would literally be cheaper for sujsuj to buy a low-cost petrol chainsaw rather than make up an extension lead to that spec.... with the added advantage of a petrol saw being far more suitable for tree work than one with a cord - from the POV of both electric shock risk and entanglement risk.  Corded electric chainsaws are not a good choice for working on standing trees.

grumbler

Section62 said:

ThisIsWeird said:

sujsuj said:

Jonboy_1984 said:

They said on the second page its a garage socket, my guess is someone installed a pre-loaded consumer unit in the garage, and the unmarked 20A's are not connected to anything.

That is why I am wondering what else is plugged in on the same 16amp circuit.

For More clarity, I tried chain saw directly and with extension in 2 sockets...

1.  Garage socket , remember there is a connection from Garage to the Gate control CAME as well. Game control is always plugged  & ON. When I tried direct  chainsaw in socket it worked and MCB tripped when connected with extension.
2. Conservatory Socket - There was a exercise Vibration machine also  worked from that socket, but tried after removing that machine only. When I tried direct  chainsaw in socket it worked and plug 13A fuse spoiled  when connected with extension.

I may have to try again to see if same results again. Also I have a third extension cable to be tried though it is smaller 10M one.

A 13A fuse blew when you used the socket in the conservatory? 
There is surely something more amiss here? 
'Fuses' are relatively slow- blowing, so I'm struggling to think of what condition - other than a fault with the extension cable - could make this happen.
Yes, two cables are seemingly affected, but I've just had two PV inverters come up with the exact same - and very unusual - fault within minutes of eachother. That blew my mind, nevermind anything else.

Motor starting currents can be mind blowingly high. It isn't clear the type of motor in this chainsaw, but as an example, an induction motor in locked rotor condition could draw up to 10 times the nominal running current.  If you do the voltage drop calculation using those levels of current and a long length of cable, then consider the effect of low volts on current draw for a large motor in locked rotor/startup, then it isn't difficult to figure it out.

Again, a long cabla can make this current only lower, not higher. I stick to my guns - if the extension cable isn't faulty it can't make things worse.

ThisIsWeird

Section62 said:

Motor starting currents can be mind blowingly high. It isn't clear the type of motor in this chainsaw, but as an example, an induction motor in locked rotor condition could draw up to 10 times the nominal running current.  If you do the voltage drop calculation using those levels of current and a long length of cable, then consider the effect of low volts on current draw for a large motor in locked rotor/startup, then it isn't difficult to figure it out.

Totally get what you are saying. Yes, starting currents are typically much higher than running. 

It seems astonishing that a 'saw clearly designed for normal domestic use, and being supplied via a correctly-rated 25m* extension cable designed for ditto, can cause this issue, especially with a fuse. Wouldn't this situation be repeated all over the country?!

*I'm still not clear whether SS is using both to achieve 50m, or each separately.

Eldi_Dos

sujsuj said:

Eldi_Dos said:

sujsuj said:

Section62 said:

sujsuj said:

grumbler said:

Jonboy_1984 said:

They create additional resistance (and heat) when coiled due to the magnetic fields.

I think, magnetic field is a myth as cable has two cores with opposite currents.

And, again, heat (poor dissipation in this case) on its own cannot cause MCB tripping

RCD tripped

sujsuj said:

tripped switch highlighted

That isn't an RCD you've highlighted.  It is an MCB.

Move your wood pile closer to the power source... will be easier, safer and cheaper.

But I am cutting a tree branch!

Pruning saw would be cheaper and more efficient with the benefit you could use in damp conditions.

I got a Pruner and I think there is a saw attachment as well. But I thought it can be used for small branches only and manual labour more needed as well

A pruning saw sized to suit the branches you are dealing with is the tool designed for the job. Along with the correct PPE.

Be very wary of the work you intend doing, after the great storm of 1987 I believe more people came to grief using chainsaws in the clear up than during the storm itself.
The potential energy in a branch can very rapidly become kinetic energy which you do not want to get in the way of.

sujsuj

Eldi_Dos said:

sujsuj said:

Eldi_Dos said:

sujsuj said:

Section62 said:

sujsuj said:

grumbler said:

Jonboy_1984 said:

They create additional resistance (and heat) when coiled due to the magnetic fields.

I think, magnetic field is a myth as cable has two cores with opposite currents.

And, again, heat (poor dissipation in this case) on its own cannot cause MCB tripping

RCD tripped

sujsuj said:

tripped switch highlighted

That isn't an RCD you've highlighted.  It is an MCB.

Move your wood pile closer to the power source... will be easier, safer and cheaper.

But I am cutting a tree branch!

Pruning saw would be cheaper and more efficient with the benefit you could use in damp conditions.

I got a Pruner and I think there is a saw attachment as well. But I thought it can be used for small branches only and manual labour more needed as well

A pruning saw sized to suit the branches you are dealing with is the tool designed for the job. Along with the correct PPE.

Be very wary of the work you intend doing, after the great storm of 1987 I believe more people came to grief using chainsaws in the clear up than during the storm itself.
The potential energy in a branch can very rapidly become kinetic energy which you do not want to get in the way of.

Can you be more clearer on last line..? Are you saying cutting braches loose Trees balance and results in them falling during storm..?

sujsuj

ThisIsWeird said:

Section62 said:

Motor starting currents can be mind blowingly high. It isn't clear the type of motor in this chainsaw, but as an example, an induction motor in locked rotor condition could draw up to 10 times the nominal running current.  If you do the voltage drop calculation using those levels of current and a long length of cable, then consider the effect of low volts on current draw for a large motor in locked rotor/startup, then it isn't difficult to figure it out.

Totally get what you are saying. Yes, starting currents are typically much higher than running. 

It seems astonishing that a 'saw clearly designed for normal domestic use, and being supplied via a correctly-rated 25m* extension cable designed for ditto, can cause this issue, especially with a fuse. Wouldn't this situation be repeated all over the country?!

*I'm still not clear whether SS is using both to achieve 50m, or each separately.

Using one extension at a time, not both extension cables together

Section62

ThisIsWeird said:

It seems astonishing that a 'saw clearly designed for normal domestic use, and being supplied via a correctly-rated 25m* extension cable designed for ditto, can cause this issue, especially with a fuse. Wouldn't this situation be repeated all over the country?!

Possibly, but there are also site-specifc factors in play here.

It looks like sujsuj's home is in a relatively rural area, so the mains supply to the house may not be that good.  We know nothing about his house wiring, nor the cable from the house to the shed/garage.

The cumulative effects of these may mean that this extension lead + saw combination is a problem for sujsuj, but may not be for someone else.

Equally, there could be a fault with the manufacture of the extension lead(s) which is causing excessive volt-drop.... although with two different makes involved this wouldn't be top of my list.

When the manufacturer goes to the trouble of specifying a maximum impedance for the supply the saw can be used on then this - in my view - gives a very big clue about the quality of supply this saw is designed to be used with (and gives the manufacturer a get out in cases like sujsuj's).

Eldi_Dos

sujsuj said:

Eldi_Dos said:

sujsuj said:

Eldi_Dos said:

sujsuj said:

Section62 said:

sujsuj said:

grumbler said:

Jonboy_1984 said:

They create additional resistance (and heat) when coiled due to the magnetic fields.

I think, magnetic field is a myth as cable has two cores with opposite currents.

And, again, heat (poor dissipation in this case) on its own cannot cause MCB tripping

RCD tripped

sujsuj said:

tripped switch highlighted

That isn't an RCD you've highlighted.  It is an MCB.

Move your wood pile closer to the power source... will be easier, safer and cheaper.

But I am cutting a tree branch!

Pruning saw would be cheaper and more efficient with the benefit you could use in damp conditions.

I got a Pruner and I think there is a saw attachment as well. But I thought it can be used for small branches only and manual labour more needed as well

A pruning saw sized to suit the branches you are dealing with is the tool designed for the job. Along with the correct PPE.

Be very wary of the work you intend doing, after the great storm of 1987 I believe more people came to grief using chainsaws in the clear up than during the storm itself.
The potential energy in a branch can very rapidly become kinetic energy which you do not want to get in the way of.

Can you be more clearer on last line..? Are you saying cutting braches loose Trees balance and results in them falling during storm..?

Do not think I can be clearer really.

Section62

grumbler said:

Section62 said:

ThisIsWeird said:

sujsuj said:

Jonboy_1984 said:

They said on the second page its a garage socket, my guess is someone installed a pre-loaded consumer unit in the garage, and the unmarked 20A's are not connected to anything.

That is why I am wondering what else is plugged in on the same 16amp circuit.

For More clarity, I tried chain saw directly and with extension in 2 sockets...

1.  Garage socket , remember there is a connection from Garage to the Gate control CAME as well. Game control is always plugged  & ON. When I tried direct  chainsaw in socket it worked and MCB tripped when connected with extension.
2. Conservatory Socket - There was a exercise Vibration machine also  worked from that socket, but tried after removing that machine only. When I tried direct  chainsaw in socket it worked and plug 13A fuse spoiled  when connected with extension.

I may have to try again to see if same results again. Also I have a third extension cable to be tried though it is smaller 10M one.

A 13A fuse blew when you used the socket in the conservatory? 
There is surely something more amiss here? 
'Fuses' are relatively slow- blowing, so I'm struggling to think of what condition - other than a fault with the extension cable - could make this happen.
Yes, two cables are seemingly affected, but I've just had two PV inverters come up with the exact same - and very unusual - fault within minutes of eachother. That blew my mind, nevermind anything else.

Motor starting currents can be mind blowingly high. It isn't clear the type of motor in this chainsaw, but as an example, an induction motor in locked rotor condition could draw up to 10 times the nominal running current.  If you do the voltage drop calculation using those levels of current and a long length of cable, then consider the effect of low volts on current draw for a large motor in locked rotor/startup, then it isn't difficult to figure it out.

Again, a long can make this current only lower, not higher. I stick to my guns - if the extension cable isn't faulty it can't make things worse.

Yet sujsuj's clarifications have made it clear - there is consistency in the chainsaw working when plugged into a wall socket, and not working when plugged in via an extension.  In both cases the tripped device is an overcurrent one, not earth leakage.

What fault do you believe the extension lead could (in theory) have which would result in it passing more current to the chainsaw than the chainsaw will draw when plugged in directly to a wall socket?

Unless sujsuj isn't describing the situation accurately there is a clear cause and effect involved here.  This isn't some random nuisance tripping of a faulty MCB.