Hey @silverback
That all looks brilliant.
You’ve done well to work with an electrician in that way. (Maybe is he a good friend) ? As electricians have to “sign off” or certify electrical work, many will want to ensure it’s all done to standard and wish to do it themselves. ( Refer to 18th edition, Part P, etc).
Did you install the 10mm into the MK switch less faceplates for yourself ? How were your finger tips 
All credit. Wishing you lots of luck
R
Lots of questions raised in this post. Maybe too many to explore here. (Avoiding thread drift, etc).
By coincidence a new thread “Dedicated Mains”, has just started tonight. So, maybe join in and ask your questions there…
In-the-meantime, for what it’s worth, it just works. Results are very worthwhile for Naim audio systems. However, appreciate not everyone’s situation allows such work.
Good luck
R
We have worked in a similar situation but I’m more engineering based but we both have a good understanding of each other fields but basically I do the donkey work he checks it and carries out the technical part, he knows I work to a high standard so it results in everyone benefitting.
He said I’m the best apprentice he has had, cheeky sod😂
My nDac is set to chassis , but ND5XS2 is set to default.
Given your post I’m assuming I should change that to be floating.
Can you explain why and what this does?
Hoping for more SQ gains 
I’m no technical expert but you only need one of them set for grounding purposes. In your case the nDac and ND5XS2 are both trying to be grounded. You should try setting your ND5XS2 to float I bet you’ll notice increased SQ.
Done… and yes there’s an improvement. Thank you for this!!
The way Naim systems are grounded is by using a single ground for all boxes, so the signal ground runs from power amp to preamp to source, and from source to mains earth. It’s important that it only connects to mains earth at one point. In this case, it’s your NDAC that does this for the whole system (assuming that you do not also have a Naim CD player) and it should be set to Chassis.
Your streamer is connected by an SPDIF cable, which doesn’t carry the signal ground so it’s not part of the whole system ground. If it, and your NDAC, were both connected to your preamp you would set it to floating, but it’s not. Just set it to whatever sounds best.
Just had an update from the courier ndac should be here in the morning, think I have everything covered, we have shelf space,BNC adapter for the chord digital cable, sorted for grounding, thanks to advice from forum members.
Understand I need to reset the output for the Nd5xs2 from din to BNC and hopefully we will have music unless there is something else I need to do?
Smile and enjoy
I certainly hope so and thanks for all your advice plus the heads up regarding Signals 
Quick question regarding din connection from ndac to 282, ndac manual is saying use aux1 on preamp, connection guide is showing aux2, I would of put it in the cd input of the 282 seems a little confusing especially as aux1&2 are also powered.
Can some kind member just clarify for me, thanks. I’m
Thanks for the explanation…
I’ve set the ND5XS2 to floating and it’s given things a real boost…
We use nDAC into CD on 252
My ND5XS2 is on the default chassis setting but I don’t think will make much difference using the ND5XS2 as a transport…
Mine will take another week to arrive here, so in the meantime I’m looking forward to your impressions!
The ndac has arrived just need to get a few jobs out of the way then hopefully later on I will get it into my system, it’s a bit like being a kid at Christmas, hope my expectations will come to fruition been waiting a long time for this.
@silverback Found that paperwork…
Looks like the bill for a new replacement top cover / panel was £64.00, fitted.
Dealer invoice was dated March 2019.
Hope that helps?
R
Cheers for that ratrat, not too bad really, will have to look into that cheers.
@dmu
Hi dmu. Thinking about your recent post…
Just seen another one with Signals…
This one is a bit older than the last one they had. But lower (better) price reflects this…
Given what you’ve said, appreciate it’s maybe too soon for you. But thought to mention it anyway. I’ll keep a look out in the longer term.
Good luck
R
edit : Signals make reference to upgrading an nDAC with NPX300. This is incorrect and categorically not possible. Don’t know why they say that ? This advice should read XPS or 555PS, or their DR versions (only).