Power supply trips CU

I bought a 12volt 8.5amp TDK Lambda power supply from Radio Spares to 
replace a Mean Well 12v 8.5a supply which had failed after 3 years.

https://uk.rs-online.com/web/p/embedded-switch-mode-power-supplies-smps/8139099/?sra=pstk

I connected it up to a 3 pin plug with a 13A fuse. When I plugged it in 
to an extension socket, which had a 13amp fuse, to check the output 
voltage, it tripped the CU , and the said extension socket blew the fuse.
Any ideas as to why.

Thanks

RobH wrote:

> it tripped the CU

MCB or RCD?

On 28/10/2020 15:57, Andy Burns wrote:
> RobH wrote:
> 
>> it tripped the CU
> 
> MCB or RCD?

I don't know, how can I tell.

On 28/10/2020 16:01, RobH wrote:
> On 28/10/2020 15:57, Andy Burns wrote:
>> RobH wrote:
>>
>>> it tripped the CU
>>
>> MCB or RCD?
> 
> I don't know, how can I tell.

It's a Concactum DDS10166-P01 CU, just installed about 18 months ago

RobH wrote:

> Andy Burns wrote:
>
>> MCB or RCD?
> 
> I don't know, how can I tell.

Does the individual breaker that tripped have a "test" button on it?

On 28/10/2020 16:07, Andy Burns wrote:
> RobH wrote:
> 
>> Andy Burns wrote:
>>
>>> MCB or RCD?
>>
>> I don't know, how can I tell.
> 
> Does the individual breaker that tripped have a "test" button on it?
> 

Yes it does, about 40mm to 70mm from the right hand side

RobH wrote:

> Andy Burns wrote:
>
>> Does the individual breaker that tripped have a "test" button on it?
> 
> Yes it does, about 40mm to 70mm from the right hand side

Implies earth leakage from the power supply, nothing rattling around 
inside the PSU, or stray strands of wire where it's been connected? 
(could also explain it blowing a fuse)

On 28/10/2020 17:00, Andy Burns wrote:
> RobH wrote:
> 
>> Andy Burns wrote:
>>
>>> Does the individual breaker that tripped have a "test" button on it?
>>
>> Yes it does, about 40mm to 70mm from the right hand side
> 
> Implies earth leakage from the power supply, nothing rattling around 
> inside the PSU, or stray strands of wire where it's been connected? 
> (could also explain it blowing a fuse)

No, nothing is rattling around inside the PSU, and the 3 core mains 
cable is securely screwed up in the 3 separate connections for +V ,-V 
and GND.

RobH wrote:

> the 3 core mains cable is securely screwed up in the 3 separate 
> connections for +V ,-V and GND

Err shouldn't it be wired to L, N and GND?

On 28/10/2020 17:12, Andy Burns wrote:
> RobH wrote:
> 
>> the 3 core mains cable is securely screwed up in the 3 separate 
>> connections for +V ,-V and GND
> 
> Err shouldn't it be wired to L, N and GND?

Ok but on the front of the psu is hows +V, -V then GND , then L and N
That's from left to right.
Have I wired it wrong , and it should be L,N and GND, doh!