You really don’t need that 3A fuse.
Yes true but its still perfectly usable and considering the price of copper at the moment. If it bursts then so would 1mm wall thickness if its a freeze situation its just the french over the top standard. Not my problem but I would let that one go.
Actually I agree - as I said I used “sub standard” pipe myself so I can hardly call someone else out for bringing 22mm from the UK.
15mm is a different kettle of limescale though 
1 Like
Its the manufacturers spec and as you say protects the wiring but in this case could be the units internal wiring rather than the supply cable. It could be internal wires 0.5mm so something inline to hopefully go first.
I am old enough to remember when 15mm came out and the old 1\2" wouldnt marry up in some situations. Likewise 3/4" and 22mm.
1 Like
Sort of - it’s how it would typically be supplied with 240V in the UK and the 3A rating a function of the expected power draw and the fact that the “spur” might well be flex coming out of one of these
If this is needed there should be a separate internal fuse.
As an aside it still makes me nervous that you can have a “sortie de cable” in France with no fuse involved.
In any case a modern disjoncteur may well trip faster than a fuse will blow under “moderate” overload conditions.
1 Like
Possibly related to the French preference for hard soldering their plumbing.
1 Like
They most certainly do, I have them coming to me this afternoon to update their previous OK’s on four apartments that were passed over fifteen years ago. Everybody does know that rentals have a finite time limit as per Consuel passes before they have to be updated, don’t they?
TBH no 
I last dealt with them for the business back in 2011 and just wondered if they had been superceded by some other new authority which seems to be normal these days. I did look on the tomes of papers for this house and it had a copy of their certificate of conformity via the builders.
Thanks Wozza, I’m not doing anything outside in this weather! never heard of one of those yes it is an industrial pump designed for foul water. However I’ll do some basic tests as badger suggested then get the leccy back or contact German pump manufacturer, if it’s not leakage, hopefully leccy will have some whizzy tool to measure other stuff.
Whilst theoretically true/applicable the OP states that the pump runs just fine without a différentiel i.e. whatever disjoncteur is running it copes just fine with the start inrush current.