Part P and garden electrics

[ARWadsworth]

anyone spot any errors?

[F Murtz]

What is a 50 cm rubber cable?

[Brian Gaff]

At a stretch probably a non conductive one?

Brian

[F Murtz]

A big giant large one (tautology)

[John Rumm]

How many do you want ;-)

I am dubious about the whole "its not under part P because its plugged in" excuse... basically if its a permanent installation, of fixed equipment then its notifiable*

Cable fixed to temporary structure (fence panel).

No comments on ensuring cable trench is free of sharp stones / lining with sand if required etc.

The custom plug and socket bit seems like a nice little earner - rather than provide an outdoor socket that can take a normal BS1362 plug, get them to buy new plugs so they fit their dangly "soap on a rope" sockets.

The "Prevents household RCD activation on faults up to 30mA. Garden Circuit Breaker working at 25mA means that your house mains electric supply (30mA) WON?T be cut, should you experience an outdoor electrical fault (between 25-30mA)." seems like a round about way of saying "your CU RCD will probably trip!"

Having said all that, its better than the semi permanent installation of a bog standard extension lead.

• while I appreciate that means it gets treated with all the respect that it should usually be accorded.

[A.Lee]

I'd say they get round that by decribing it as a 'pre-fabricated equipment set', 521.100. I t doesnt need notification to BC if it is not in a special location, if it is: "a prefabricated equipment set and associated flexible leads with integral plug and socket connections"

- from page 8 of Building Regs Part P. Which is probably why they use their own connections too.

No, I'm not a walking Part P and Regs book - I did a Building Regs course yesterday, and this came up in the 'notify or not' section.

[ARWadsworth]

You and Andy Wade were the two people I thought of when I posted the link:-)

there a 25mA RCD in the British Standards?

[Robin]

Is there one the other way - ie where they are overstating the law - in the comment "If you currently use power products in the garden they must, by law, be run by a RCD"? I appreciate that current and recent iterations of the regs have required RCD protection for sockets likely to be used for power in the garden but I wasn't aware of a law against me being an idiot if I want to with an unprotected socket which complied with the regs when it was installed.

[ARWadsworth]

:-) IKWYM

Page 2 says (sorry for the capital letters I copied and pasted the box from page 2 of the pdf)

POWERSAFE PRODUCTS COMPLY WITH LEGAL ELECTRICAL SAFETY STANDARDS.

ELECTRICAL STANDARDS STATE THAT:

. ALL OUTDOOR POWER SUPPLIES MUST BE PROTECTED BY A CIRCUIT BREAKER. . ALL OUTDOOR ELECTRICAL COMPONENTS MUST COMPLY WITH OUTDOOR WEATHERPROOF SAFETY STANDARDS. . ALL POWER SUPPLIESACROSS THE GARDEN MUST BE CARRIED BY METAL SHEATHED ARMOUREDCABLE. . IF BURIED, WARNING TAPE MUST BE APPLIED.

Is a circuit breaker a RCD? Do they mean a plug in RCD circuit breaker? They do not mention an RCD in that part of their pdf and I would not expect a normal circuit breaker to include RCD protection. Am I breaking the law by not using a plug in RCD even though I am using a 30mA RCD protected socket?

Of course I only made the post because I am an annoying bastard who likes to find fault with companys that cannot get things right. But you already knew that.

Blagdon will be getting an email and a phone call from me. Any words of wisdom are welcome before I give them a bollocking for uploading such a pile of s**te onto the internet.

[Andy Wade]

The standard for plug-in RCDs seems to be non-harmonised - BS 7071:1992 (confirmed 2007). This talks in terms of 'rated tripping current' - for which no preferred values are given. So any value that the manufacturer cares to give it would seem to be OK. (In contrast the familiar BS EN

61008 for consumer unit RCCBs gives 'preferred' I-delta-n values of 10, 30, 100 and 300 mA.)

The tripping characteristics in BS 7071 are the usual ones: it must not trip at half the rated I-trip, and must trip at I-trip - so 12.5 to 25 mA in this case.

Their hope of achieving discrimination with a house RCD is of course fanciful - you'd need an isolating transformer to achieve that.

It's unfortunate that in the 'Tech Specs' the supply frequency is given in units of inductance and the trip speed in units of conductance - no technical proofreader, clearly.

Nevertheless it's a well-intentioned attempt to provide a kit that allows a non-electrical-specialist to do a safe-enough job, I think.

[The Medway Handyman]

I install quite a few electric patio awnings & the manufacturers instructions say that if it's plugged in rather than wired in, it doesn't need to be notified.

[John Rumm]

Which is fine, up to the point you install your permanent equipment such as the pond pump... at which point the means of connection becomes irrelevant ;-)

[John Rumm]

Given its fixed to the outside wall of the house most likely, then it would be unlikely to anyway[1]. (the "plugged in" get out is a misnomer, in much the same way a boiler connected via a plug and socket is still fixed equipment)

[1] An outside light or single socket mounted that way would also be ok.

[charles]

my pond pump is plugged in to a 134A outlet. what is permanent about that?

[John Rumm]

In fairness, it could be much worse... they overstate some bits, gloss over others etc, but its a reasonably well thought out system. A numpty would have to try somewhat harder to create a death trap with one of those kits than if left to their own devices.

Their pre-assembled SWA gland combi also possibly gets round the problem of "tool-less" access to a TN-C-S earth in a location with access to and independent earth reference.

[SteveW]

Well it probably takes a hell of an effort to get the plug out and move the cable ;)

SteveW

[Nick Odell]

Bloimy! Are you trying to emulate the Lake Geneva fountain or something?

Nick

[ARWadsworth]

I just wabt them to correct the errors. The kit itself seems OK

[news]

Is there a way on ensuring the local rcd would trip first? My boss has a submersible pond pump on the same circuit as his garage, with his freezer. When the pump went west it tripped the rcd on the consumer unit and stopped the freezer.

AJH

[John Rumm]

The only way to reliably discriminate with cascaded RCDs is to use a time delay RCD at the head end[1]. That way even if a leakage current is applied to the circuit that is adequate to trip both, the downstream one will trip first and hopefully clear the fault before the higher up one decides its time to trip.

Attempting to discriminate on trip current alone is unlikely to be successful, since many real world faults will produce enough leakage to trip both, and then you just have a race condition as to which (or both) get their first.

[1] these require the fault to be present for a few tens of ms, before they trip. Hence they are fine for circuit and fire protection, but no use for shock protection.