Faac c721 shorting power on mains

Gatehelp · May 10, 2022

Hi, I have installed a faac c721 with 4 Photocells and everything we connect the transformer it trips the power in the house. We have tested and we get 250v but cannot understand why it keeps shorting the circuit. The c721 is just sat on driveway can't get around it. Has anyone noticed problems with this before - the transformer could just be a smoke screen it's brand new only a couple of weeks old. Faac have said send it back for testing but that's a nightmare with all the blockwork settled back in. I have the nylon racking off also. Any help would be grateful.

[ElectriciansForums.net] Faac c721 shorting power on mains

DPG · May 11, 2022

Is it tripping an RCD, RCBO or MCB?

Gatehelp · May 11, 2022

DPG said:
Is it tripping an RCD, RCBO or MCB?

Hi, it was strange it was a mixture but mostly the RCD circuit but I have shown here which ones are tripping. The first time all 3 tripped and then it was mostly RCD on the testing.

UNG · May 11, 2022

What testing have you done
Where are you measuring the 250v if the circuit keeps tripping

DPG · May 11, 2022

What are the IR test results?

UNG · May 11, 2022

Gatehelp said:
Hi, it was strange it was a mixture but mostly the RCD circuit but I have shown here which ones are tripping. The first time all 3 tripped and then it was mostly RCD on the testing.View attachment 97397

Is it one or both RCD's that are tripping

snowhead · May 11, 2022

Is the gate motor unit connected to an existing circuit or a new one?
Is there anything else inside or outside that is also connected to that circuit?
Either way can you identify which MCB on the consumer unit that circuit is.

Julie. · May 11, 2022

Have you tried connecting the transformer alone (no secondary connections) ?

What size transformer is it?

Might help to post a picture of the transformer and its connections.

As asked above what is the ir reading L+n to earth?

Gatehelp · May 11, 2022

UNG said:
Is it one or both RCD's that are tripping

Hi, it was all 3 on the first test and then 1 RCD and then 2 RCDs on another test. We noticed it was when the transformer was connected that's when it tripped. Plugging everything else in one by one and then pop when the transformer was plugged in.

Gatehelp · May 11, 2022

UNG said:
Is it one or both RCD's that are tripping

Hi, it is a mixed bag. On the first test both RCD's tripped and on other tests 3 tripped and then 1 RCD tripped

DPG · May 11, 2022

What test equipment do you have? Are you able to carry out some basic IR tests?

UNG · May 11, 2022

Gatehelp said:
Hi, it was all 3 on the first test and then 1 RCD and then 2 RCDs on another test. We noticed it was when the transformer was connected that's when it tripped. Plugging everything else in one by one and then pop when the transformer was plugged in.

Your reply seems to suggest that all your "testing" is purely a plug in and wait for the RCD to trip, have you got the necessary test equipment to carry out dead testing and subsquently the live testing
Your profile indicates you are a trainee electrician are you working with someone who is qualified on this job

Gatehelp · May 11, 2022

Julie. said:
Have you tried connecting the transformer alone (no secondary connections) ?

What size transformer is it?

Might help to post a picture of the transformer and its connections.

As asked above what is the ir reading L+n to earth?

snowhead said:
Is the gate motor unit connected to an existing circuit or a new one?
Is there anything else inside or outside that is also connected to that circuit?
Either way can you identify which MCB on the consumer unit that circuit is.

Hi, thanks we have a fuse switch spare and a safety isolator switch connected to the circuit going from the one right of number 5 on the fuse board. Nothing else is connected to number 5 on the fuse board.

Gatehelp · May 11, 2022

UNG said:
Your reply seems to suggest that all your "testing" is purely a plug in and wait for the RCD to trip, have you got the necessary test equipment to carry out dead testing and subsquently the live testing
Your profile indicates you are a trainee electrician are you working with someone who is qualified on this job

Hi, yes 100% i am no expert but this was carried out by an electrician and has left it all unplugged - just trying to see for some help. I deal more in access control configuration so my job comes in when the unit is connected and programming it

Julie. · May 11, 2022

Gatehelp said:
Hi, thanks we have a fuse switch spare and a safety isolator switch connected to the circuit going from the one right of number 5 on the fuse board. Nothing else is connected to number 5 on the fuse board.

It could be a fault with the secondary wiring - can't tell unless you try it without the secondary connected

It could be transformer inrush, can't tell unless we know the size of the transformer.

It could be the transformer's connected incorrectly, can't tell unless we see a photo of the Connections

It could be an internal fault within the transformer, can't tell without the ir readings

A number of people have asked a few leading questions in order to narrow the issue down, without any response without the information we will not be able to help you.

We can all have a multitude of informed guesses as to the issue, but are unable to narrow it down without the questions being answered.

Gatehelp · May 11, 2022

Julie. said:
It could be a fault with the secondary wiring - can't tell unless you try it without the secondary connected

It could be transformer inrush, can't tell unless we know the size of the transformer.

It could be the transformer's connected incorrectly, can't tell unless we see a photo of the Connections

It could be an internal fault within the transformer, can't tell without the ir readings

A number of people have asked a few leading questions in order to narrow the issue down, without any response without the information we will not be able to help you.

We can all have a multitude of informed guesses as to the issue, but are unable to narrow it down without the questions being answered.

Thank you for the responses. I agree i am out of my depth so will find another electrician my hope of it being a known issue was a load of rubbish but i thank you all for your time it is the first time me using this forum but thank you all for your help

DPG · May 11, 2022

Gatehelp said:
Thank you for the responses. I agree i am out of my depth so will find another electrician my hope of it being a known issue was a load of rubbish but i thank you all for your time it is the first time me using this forum but thank you all for your help

Did you pay the electrician for this work? I would get him back and tell him to sort it.

Or did you fit it?

Gatehelp · May 11, 2022

DPG said:
Did you pay the electrician for this work? I would get him back and tell him to sort it.

Or did you fit it?

paid an electrician who was qualified with house automation he said he would be back but hasnt come back and cant get hold of him - lesson learnt for me but will find another one and then do the automation part of it myself. Every day is a school day as they say.

marconi · May 11, 2022

Please show me a picture of how the brown, black and gray wires of the armoured cable have been connected to the green pe/N/L block bottom left of circuit board.

UNG · May 11, 2022

Gatehelp said:
paid an electrician who was qualified with house automation he said he would be back but hasnt come back and cant get hold of him - lesson learnt for me but will find another one and then do the automation part of it myself. Every day is a school day as they say.

Whereabouts in Liverpool are you based, your probably not too far from me

UNG · May 13, 2022

Looks like the OP has disappeared on this one

marconi · May 13, 2022

UNG said:
Looks like the OP has disappeared on this one

You and I though think we know what is one possible reason for the problem.

DPG · May 13, 2022

marconi said:
You and I though think we know what is one possible reason for the problem.

I suspect I think the same.

UNG · May 13, 2022

marconi said:
You and I though think we know what is one possible reason for the problem.

He is still lurking

Gatehelp · May 13, 2022

UNG said:
He is still lurking

I have another electrician booked in to come and have a look. Thanks all

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