- Thread starter Rich#1984
- Start date
brightspark
Member
- Messages
- 41,242
- Location
- yarm stockton on tees
what breaker an rcd or the minature breaker and what amperage and type is it .standard are b type domestic
Rich#1984
Member
- Messages
- 123
- Location
- Barnsley England
The main RCD switch says 240v-50Hz RCCB 80A 30MA
and the MCB for the garage is a MCB B16 if that helps at all I have no clue when it comes to electrical stuff at all the welder it's a ANDELI MP250 inverter running on a standard 13a plug
brightspark
Member
- Messages
- 41,242
- Location
- yarm stockton on tees
which one is tripping the main rcd or the 16 amp breaker . the welder should have a data plate giving the details of input amperage
Rich#1984
Member
- Messages
- 123
- Location
- Barnsley England
Newlands
Member
- Messages
- 784
- Location
- Sussex, UK
Even my 185a mig trips a 16a mcb. If your welder is actually a 250a then a B16 is not enough. You could try a C20 or a C32 (but you’ll then need to check the cabling, plugs and sockets downstream of that to make sure they are rated for the extra current).
As long as the RCD is not tripping that would suggest that there is no earth fault associated with the welder, although inverters in general sometimes do cause RCD’s to trip.
As long as the RCD is not tripping that would suggest that there is no earth fault associated with the welder, although inverters in general sometimes do cause RCD’s to trip.
On average, how many Amps are you running the welder at when it trips? What thickness are you welding, and does the problem happen in both MIG and Arc modes?
brightspark
Member
- Messages
- 41,242
- Location
- yarm stockton on tees
a c20 would be the maximum you would go to if your only on a 2.5 mm cable and should cure the problem
Bobupndown
What could possibly go wrong?
- Messages
- 1,936
- Location
- Northern Ireland
Got a 32amp dedicated welder circuit wired into my garage specifically to prevent this, I was fed up changing 13amp plug fuses on a stick welder at my old house.
B16 says it's a 16A trip - it will carry 16A comfortably, the B says its fairly fast reacting to overloads and is less tolerant to the surge that your welder puts on the circuit when it starts up. You need to replace it with a type C (or even type D) MCB - e.g. C16 or D16 if you want to keep the circuit to 16A.
I think old fashioned fuse wire was much more forgiving with welders than the modern trips are, it's why you're blowing 16A trips rather than 13A fuses
I think old fashioned fuse wire was much more forgiving with welders than the modern trips are, it's why you're blowing 16A trips rather than 13A fuses
brightspark
Member
- Messages
- 41,242
- Location
- yarm stockton on tees
a 13 amp fuse will run a good while taking 19 amps as for the breaker dont go any further than a c dont use a d type
123hotchef
Member
- Messages
- 14,343
- Location
- Kent
TUNE!
Munkul
Jack of some trades, Master of none
- Messages
- 7,768
- Location
- Cumbria
B16's are useless for decent power welders. The problem is, the more they trip under load, the softer they get, so they start tripping at lesser loads.
I'd be putting in either a C16 or a B20, after making sure the circuit wiring can handle it.
I'd be putting in either a C16 or a B20, after making sure the circuit wiring can handle it.
Realistically, us just saying uprate to a bigger/slower MCB probably isn't good advice with what we know - I'd be comfortable moving to a different MCB if it was my wiring where I know what the cable spec and circuits are - we don't really know enough of the supply to just say uprate it - it may be that the 16B is there because that's the best the cabling can handle.
I've actually changed my mind on this since since I said just bung in a type C or a D - it's not really a good idea until you have full details just to modify something like this. Remember MCB's/fuses are there to protect the wires, get it wrong and the wires will burn out and protect the fuse/MCB
There are two trip mechanisms in an MCB, there is a magnetic trip that is triggered when there is a large sudden change in current (e.g. when the welder turns on) and there is also a thermal trip which is a bit slower to act and is triggered when the current through the trip is too high for too long, e.g. when welding for a long period at high current. The type letter B C or D relates to the current that causes the magnetic trip, the number e.g. 16 is the designed carrying current the trip will carry (note I didn't say safe current - the 16 is the current that the MCB will carry - it says nothing about the safe current the wire can carry
).
This feels to me like it's a surge problem with the trip but the OP doesn't say when the trip occurs, is it mid bead ?, is it at trigger press and also what welding current is being run.
It's an inverter machine as well, it could/should have a soft start that prevents inrush currents so it could be a fault with the welder causing the trip or the MCB getting a bit old and tired and not able to cope with high currents for as long as it used to.
In short, it's a really simple question to ask but a *&('ing difficult one to answer
I've actually changed my mind on this since since I said just bung in a type C or a D - it's not really a good idea until you have full details just to modify something like this. Remember MCB's/fuses are there to protect the wires, get it wrong and the wires will burn out and protect the fuse/MCB
There are two trip mechanisms in an MCB, there is a magnetic trip that is triggered when there is a large sudden change in current (e.g. when the welder turns on) and there is also a thermal trip which is a bit slower to act and is triggered when the current through the trip is too high for too long, e.g. when welding for a long period at high current. The type letter B C or D relates to the current that causes the magnetic trip, the number e.g. 16 is the designed carrying current the trip will carry (note I didn't say safe current - the 16 is the current that the MCB will carry - it says nothing about the safe current the wire can carry
).This feels to me like it's a surge problem with the trip but the OP doesn't say when the trip occurs, is it mid bead ?, is it at trigger press and also what welding current is being run.
It's an inverter machine as well, it could/should have a soft start that prevents inrush currents so it could be a fault with the welder causing the trip or the MCB getting a bit old and tired and not able to cope with high currents for as long as it used to.
In short, it's a really simple question to ask but a *&('ing difficult one to answer
brightspark
Member
- Messages
- 41,242
- Location
- yarm stockton on tees
no way using a d type. and as for the supply he said its rcd protected . at minimum it will be 2.5 cable and can handle up to 25 amps. as i said in an earlier post maximum 20 amp mcb and that leaves a good margine for safety . mcb will not hold the full load amps that they state they are rated at
