Curious Power Issue while using Chain Saw with Extension Cable!

Risteard

As above, probably inrush current.
However DO NOT simply replace the circuit breaker with a different type. This is very much a job for a competent Electrician who understands the science involved and verification methods.

grumbler

Section62 said:

grumbler said:

Section62 said:

sujsuj said:

I was trying to cut some wood using my RYOBI 2300W 40cm Chainsaw (RCS2340B). I used extension cables 13A rated its 25 meter long. But when I connect Chainsaw at end of extension cable power trips and Chainsaw stopped working. I could connect Chainsaw directly to plug and it works.

If it is the MCB tripping then there's a good chance the issue is the volt drop over 50m of low-cost extension cable is resulting in a current draw high enough to cause the MCB to trip.  What rating is the MCB, if it is that which is tripping?  (a photo may be best)

This makes no sense. Higher cable resistance (and, as a result, higher voltage drop over the cable) can result only in lower current, that cannot cause MCB tripping.

Were you basing that on I = V / R  ....or something else?

Whatever. You cannot increase the current by adding an extra resistor in sequence, can you?

Keep_pedalling said:

grumbler said:

Section62 said:

sujsuj said:

I was trying to cut some wood using my RYOBI 2300W 40cm Chainsaw (RCS2340B). I used extension cables 13A rated its 25 meter long. But when I connect Chainsaw at end of extension cable power trips and Chainsaw stopped working. I could connect Chainsaw directly to plug and it works.

If it is the MCB tripping then there's a good chance the issue is the volt drop over 50m of low-cost extension cable is resulting in a current draw high enough to cause the MCB to trip.  What rating is the MCB, if it is that which is tripping?  (a photo may be best)

This makes no sense. Higher cable resistance (and, as a result, higher voltage drop over the cable) can result only in lower current, that cannot cause MCB tripping.

The saw is likely to compensate the lower voltage by drawing a higher current to compensate. 

 Possibly, but ultimately any motor works from the current, not from the voltage, so it can draw extra to get the needed current, not higher.

Section62

grumbler said:

Section62 said:

grumbler said:

Section62 said:

sujsuj said:

I was trying to cut some wood using my RYOBI 2300W 40cm Chainsaw (RCS2340B). I used extension cables 13A rated its 25 meter long. But when I connect Chainsaw at end of extension cable power trips and Chainsaw stopped working. I could connect Chainsaw directly to plug and it works.

If it is the MCB tripping then there's a good chance the issue is the volt drop over 50m of low-cost extension cable is resulting in a current draw high enough to cause the MCB to trip.  What rating is the MCB, if it is that which is tripping?  (a photo may be best)

This makes no sense. Higher cable resistance (and, as a result, higher voltage drop over the cable) can result only in lower current, that cannot cause MCB tripping.

Were you basing that on I = V / R  ....or something else?

Whatever. You cannot increase the current by adding an extra resistor in sequence, can you?

Quite important to understanding sujsuj's problem.

He has a largish inductive load in an AC circuit, with the additional complication of it being a motor driving a mechanism with (probably*) a fair degree of mechanical resistance.

I've not delved into the detail of this model's design, but it is a reasonable assumption that at the moment of switch-on there will be a 'locked rotor' scenario. The peak current drawn by the motor (and its duration) has more to do with the design of motor, loading, and the amount of power required to get the motor up to speed, less to do with the resistance of the cable.  Also bear in mind the cable is technically capable of carring a far greater current than 13A @230V, but is rated at 13A (or whatever) for safety and longevity.  Pure electrical resistance isn't the determining factor here - the power requirement to get the motor spinning at operational speed is.  Making the motor suffer an excessive voltage drop will make it need to work harder for longer to achieve the stable state.  And more current for longer is what can make an MCB trip.

I've had the same scenario as FreeBear and used the same solution... but that isn't one that sujsuj should contemplate.  If the chainsaw works in the wall socket, but not on the end of 50m of flex, then the problem is with the flex, not the supply.

Don't believe me?  The manual for sujsuj's chainsaw (unusually) goes as far as stating you should "Connect the product to a power supply with an impedance equal to or less than 0.33 Ω to minimise voltage fluctuations." although it doesn't explain how the user should find the impedance of their power supply, other than the less than helpful "Contact your electric power supplier for further clarification".  Suffice to say that connecting it to the end of 50m+ of not very suitable flex is unlikely to help.

(*I'd wonder whether the chain has been correctly re-tensioned and lubricated recently)

danrv

sujsuj said:

I want to make sure to buy the right one next time!  I can see Chainsaw's wire very thick compared to extension cable.  

A good 50m reel would be better if that length is required. I use a 2000w chainsaw with a Homebase 15m extension with no problem. Cable is 7mm across.

The Qualcast chainsaw has a long thick red cable although this is probably for durability rather than power handing.

Something like these.
Homebase one is just re branded Masterplug probably:

https://www.wickes.co.uk/Masterplug-4-Socket-Thermal-Cut-out-Open-Cable-Reel---Blue-50m-13A/p/160630?fix&gclid=Cj0KCQjwxuCnBhDLARIsAB-cq1plZjTjx0ABswJDRtIXmBFh8mwuTgQXaMKVHvg4laJ1TaSL9JHbiTMaAhiMEALw_wcB&gclsrc=aw.ds

https://www.homebase.co.uk/masterplug-4-socket-cable-reel-50m-yellow-black/12844313.html

sujsuj

Sorry should have been clearer..

 I tried with both ALDI Workzone 25 M 13 A as well as Masterplug 20M 13A. Both used fulled unwound  state as  wood is away from plug. Tried multiple times resulted in different outcomes..

• Got 13A fuse burned in the extension cable plug once
• Got Garage RCD tripped once as well (see photo) (second switch marked as sockets)

When I connected RIOBI directly with socket without extension cable it worked all the time!

sujsuj

TadleyBaggie said:

When you say the "power trips" is this a RCD or an MCB that trips?

RCD as shown below tripped (second switch marked as sockets)

sujsuj

Section62 said:

sujsuj said:

I was trying to cut some wood using my RYOBI 2300W 40cm Chainsaw (RCS2340B). I used extension cables 13A rated its 25 meter long. But when I connect Chainsaw at end of extension cable power trips and Chainsaw stopped working. I could connect Chainsaw directly to plug and it works.

If it is the MCB tripping then there's a good chance the issue is the volt drop over 50m of low-cost extension cable is resulting in a current draw high enough to cause the MCB to trip.  What rating is the MCB, if it is that which is tripping?  (a photo may be best)

Why the picture of a Masterplug extension?  Are you using that one as well?

Its RCD & I tried with both ALDI Workzone 25 M 13 A as well as Masterplug 20M 13A.

sujsuj

grumbler said:

Section62 said:

sujsuj said:

I was trying to cut some wood using my RYOBI 2300W 40cm Chainsaw (RCS2340B). I used extension cables 13A rated its 25 meter long. But when I connect Chainsaw at end of extension cable power trips and Chainsaw stopped working. I could connect Chainsaw directly to plug and it works.

If it is the MCB tripping then there's a good chance the issue is the volt drop over 50m of low-cost extension cable is resulting in a current draw high enough to cause the MCB to trip.  What rating is the MCB, if it is that which is tripping?  (a photo may be best)

This makes no sense. Higher cable resistance (and, as a result, higher voltage drop over the cable) can result only in lower current, that cannot cause MCB tripping.

RCD as shown in above pic

sujsuj

Jonboy_1984 said:

Are the extension cables fully unwound? They create additional resistance (and heat) when coiled due to the magnetic fields.

Yes fully unwound

sujsuj

Jonboy_1984 said:

Also what else is on the same circuit as socket, e.g. is it a kitchen socket with a washing machine, fridge, freezer etc on the same switch and what is the rating on the switch in the consumer unit?

There is a chance it’s the total load that’s exceeding the switch rating (I assume you are just running the saw rather than cutting anything when testing without the extension cables?).

When I connected RIOBI directly and switched ON from same socket all worked fine. When  I tried with both ALDI Workzone 25 M 13 A as well as Masterplug 20M 13A  it caused problems.