Jump to content

Banner.jpg.b89429c566825f6ab32bcafbada449c9.jpg

Electrical supply to observatory


Philip Benson

Recommended Posts

I have a mains feed to my observatory in the garden from a mains socket located in the lounge. The feed consists of armored cable over a length of about 80ft.  The cable then connects to two double sockets in the observatory.  I can isolate the sockets in the observatory using a switch that is also in the lounge next to the source double socket.

I am directing this question to the electricians out there by asking if I am right in thinking this feed is a spur. Is this arrangement OK by electrical regs and would it cause any potential voltage drop at the other end? Would it be better for me to run the power direct from a consumer unit instead which is in the garage?

Link to comment
Share on other sites

As a start, I would check that your work meets the "Part P" regulations. If you did it yourself, it probably doesn't.

One item in those regs. says "By law, all homeowners and landlords must be able to prove that all electrical installation work meets Part P, or they will be committing a criminal offence." And you'd have to check if that would invalidate your house insurance.

Link to comment
Share on other sites

Hi Pete,

I would never tamper with the house mains by myself. I had a local qualified electrician to install the spur. He came over and I explained what I wanted. He bought the materials and installed it all for me.  I should imagine it is illegal for a qualified electrician to carry out any work that they know would not meet the Part P regs.

Link to comment
Share on other sites

Yes what you have should be ok  as long as you have a fuseboard with RCD protection, it would be classed as a spur as it comes from a socket presumably on the house ring main, and is a single cable feeding the sockets in the observatory (spur)

Although I would have though an electrician would have suggested running straight from the fuse box, unless this was not feasible.but you say you have one in The garage so again surprised the sparky did not run from there, as that would be the proper way to do it.

Link to comment
Share on other sites

Nothing wrong with it being a spur if done properly it can be entirely legal; that's how I have mine. As for voltage drop, do you have any indication at the obsy end to suspect you have anything wrong?

 

Jim

Link to comment
Share on other sites

You can use a fused spur or connect direct to a spare way in the CU.
Volt drop is not a problem as long as you sized the cable correctly.

The fused spur will be limited to 13amps and in the obsy you will want a double pole switch as a bare minimum to isolate the supply.
You can connect sockets direct to the double pole switch but use a fused spur box for the lights, 5amp fuse will be ok.

If you use a separate way in the CU fit an RCBO in there and in the obsy fit a small CU with separate ways for sockets and lights.

If you have any extraneous metal parts in the obsy you will need to take these into account for earthing.

As far as I know a fused spur is only notifiable in certain zones like bathrooms or swimming pools.

Just to add.

If you install via the consumer unit that is notifiable.

 

Link to comment
Share on other sites

5 hours ago, pete_l said:

As a start, I would check that your work meets the "Part P" regulations. If you did it yourself, it probably doesn't.

One item in those regs. says "By law, all homeowners and landlords must be able to prove that all electrical installation work meets Part P, or they will be committing a criminal offence." And you'd have to check if that would invalidate your house insurance.

Basically the Part P electrical was simplified.

The only notifiables under regulation 12(6A).

the installation of a new circuit;
the replacement of a consumer unit;
any addition or alteration to existing circuits in a special location.
 
and also wiring regs are not law, they are guidelines but of course they can be used against you in a court of law.
Link to comment
Share on other sites

You can only spur off one socket per socket on a ring final circuit with a 32A MCB and 2.5mm2 T&E.    Anymore is not allowed. A radial final circuit is different and should be 4mm2 with a 32A MCB.  If the spur is a FCU (Fused Connection Unit) you can run as many sockets as you want as that cable is protected by a 13Amp fuse max.  More of a concern is what size cable is the SWA it should be a minimum of 2.5mm2.  When installed tests (r1 +r2, Insulation, Polarity, Zs and RCD times) should have been carried out which would indicate whether is is fused at the correct rating and meets disconnection times

 

Part P and the 17th Edition Regulations are two different documents although there is some crossover and Part P only applies to domestic and not Commercial or Industrial where the 17th Edition is more relevent

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.