Shower in a petrol station?

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I have been asked to install an electric shower in a petrol station.

The room (currently a toilet) is accessed directly from outside and will contain just the shower and a changing area.

There is a 3 phase Hager CU already with RCD protection and spare capacity in a corridor just backing onto this room, and a loft space above it.  so it looks to be a straightforward job.

But I am just asking if any other regulations apply as it is part of a petrol station building.  I would not be doing any work on the forecourt or to any forecourt equipment and not even doing anything in the shop.

So would any other regs apply other than normal bathroom stuff?

 
Not done any petrol station work for years but I can offer that  , as I remember it ,    the shop is  normal wiring ,  TN-C-S    ( PME)  supply is not permitted , special areas are obviously the pumps  and  possibly the canopy .  

I'd guess you'd be fine working in the area you describe .    

Someone will probably have petrol station experience .  

 
Thanks Deke, that is what I thought but wanted a sanity check.  I will use whatever earthing is there I am not going to mess with the distribution system, just add one circuit to the existing DB.

One would feel certain that it has regular EICR's and any non satisfactory items have been dealt with.

Just an EIC for my new circuit making it clear that is all it covers.

 
Normal setup is TT, petrol station uncommer unit which contains an MCCB with earth leakage shunt trip, often with a label saying they should be adjusted to consultants spec, but normally found wound up to full. RCBOS fitted are nomrally double pole in order to avoid a N-E fault knocking out the main trip. In older installations it might only be sockets and forcourt equipment with a separate rcd/rcbo to meet the 0.2sec disconnection time (the main trip is normally set up to meet the 1sec disconnection times). however as all final circuits <32A require the reduced disconnection time you generally need an RCBO (double pole) on all circuits.

 
Interesting.  I didn't perhaps pay as much attention as I should have,

The DB is a Hager 3 phase board and it definitely had an rccd as the incomer.  All existing single and 3 phase circuits are just simple mcb's. Single phase circuits appeared to be on single pole mcb's and that is what I was planning for this shower.  Indeed I am at a loss to know how you would connect a 2 pole mcb for a single phase circuit into a Hager 3 phase board?

 
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I'm thinking a 40A  MCB  in the Hager board  ..then a remote 30mA   RCD  for the shower   .     Can't see what else you can do  TBH  . 

If you do anything else there you'll need to up your insurance to £100,000,000  cover 

 
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Mine excludes petrol storage equipment, but includes shops and offices.

I have just queried with the insurer and they say as long as I am not touching the forecourt equipment it is just treated as a "shop" and is covered.

 
Interesting.  I didn't perhaps pay as much attention as I should have,

The DB is a Hager 3 phase board and it definitely had an rccd as the incomer.  All existing single and 3 phase circuits are just simple mcb's. Single phase circuits appeared to be on single pole mcb's and that is what I was planning for this shower.  Indeed I am at a loss to know how you would connect a 2 pole mcb for a single phase circuit into a Hager 3 phase board?


What is the main RCD, as we are perhaps talking about a slightly smaller setup than I was thinking, I'm guessing we are taking 61008 time delay, at either 100mA or 300mA? At least with that the main trip will provide the 0.2 disconnection times for the final circuits (even a time delay RCD till trip within 200ms at 2XIn*)

This is from 61008, I'm never sure why we dont need to test it at 2xIn *shrugs* ...follwing on from this one would expect if the required current to acheive disconnection time is 2x RCD rating, that the max zs for the cirucits should be stated as 50v over 2x In on the paperwork (rather than 50v over In) , however I've never seen that in any text book, its just what makes logical sense to me

Anyway, a bit moot as you need 30mA additional protection for the shower, while normal practice is to use DP RCBOs, the designer might accept a lack of descrimination in terms of N-E faults by arguing:

a) there is none on any of the other rcbo circuits, and the cirucits on MCBs will take the main trip out on faults anyway

b) N - E fault on the shower is unlikely and if it does occur, the user could easily isolate it at DP switch and reset, unlike say an outside lighting circuit

c) the services that would be lost are maybe not that critical in a smaller station, loosing the fuel console and the card reader is still a pain when folk have just filled up and want to get off though, but I'm guessing there won't be servers or anything else like that

Not sure if hager do DP RCBOs for their boards, some other makes do, they take up two spaces, so if the cirucit is on 1L1, it'll also occupy 1L2, but where the second busbar terminal would normally be on a 2 pole device, there is a void space for the tab to slip into and no connection to be made, and a flying neutral comes out somewhere as per a standard RCBO. The output terminals are much easier to connect to than a single module RCBO as they are not stacked on top of each other

To summise, I wouldn't design a new installation with the N-E discrimination problem, but I'm not sure I'd worry about adding one circuit to an installation so designed,.

 
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