testing fcu with built in rcd

[monkey5]

hope someone can help. ive fitted my first fcu with built in rcd today for a power shower feed. all went fine until i came to the rcd test. there are no rcds or rcbos in the existing installation hence the reason for me fitting a FCU-rcd. tried testing at shower but test meter kept saying less than 100v so wouldnt do test. checked the voltage and it was 233v. tried testing at fcu on load side got 230v but as soon as i tried to rcd test got same problem - less than 100v. tester is megger 1552. is there a different method of testing these as opposed to an rcd or rcbo in the consumer unit. also are these an bs7288.

cheers wayne

 

[NozSpark]

You fitted a RCD fused spur to a shower???

I hope it's a pumped one and not instantaneous

 

[monkey5]

yeah its a power shower so fcu (3A) is just to supply the pump inside.

 

[Lurch]

You fitted a RCD fused spur to a shower???I hope it's a pumped one and not instantaneous

Pumped showers are often called power showers, just as instantaneous ones are often called electric showers.

 

[NozSpark]

Pumped showers are often called power showers, just as instantaneous ones are often called electric showers.

and Joe public calls them all sorts of things!!

 

[Andy™]

whats the Zs?

some RCD spurs have 2 earth terminals, and are electrically isolated from each other. if you put one earth in each, then you havent connected the earth.

if this isnt the problem, i assume you have connected the probes in the same way/terminals that you did your Zs from?

 

[monkey5]

hi andy, i did seperate the earths, should i have put them in the same terminal or maybe swap around? didnt do zs on ew circuit as got late (well 4.30 but pitch black) and was messing around with rcd test. im going back tomorrow.

i tried testing at the shower end too, if i had connected earths into wrong terminal would this also cause the test not to work?

 

[tom1]

aren't u surposed to link the earths

 

[monkey5]

aren't u surposed to link the earths

i didnt realise they arent connect internally, i thought like on a double socket with 2 earth terminal they would be connected.

 

[tom1]

i didnt realise they arent connect internally, i thought like on a double socket with 2 earth terminal they would be connected.

the instructions are really crap, it says for general use the earths should be linked. my mate says the ones he gets come with a link, not 100% on this i have not done many

 

[monkey5]

there were no instructions with it thats how crap they were!

 

[mercurystar999]

Why wouldn't the earths be connected internally?

 

[Apache]

Likely needs a link. We have had this before

http://www.talk.electricianforum.co.uk/showthread.php?t=2765

 

[Apache]

Why wouldn't the earths be connected internally?

A simple continuity test would reveal all!

 

[mercurystar999]

Agreed, but why aren't they already? Can't think of a reason not

 

[monkey5]

think you may have sorted it with that link patch, ill link out tomorrow and see if it works, its a volex too so looks like it could be.

thanks all

 

[Apache]

Agreed, but why aren't they already? Can't think of a reason not

Read the thread I linked!

3/ Or its not uncommon for FCU's & Socket outlets to have two earth terminals to allow compliance with high CPC current circuits, e.g. IT equipment REG 543.7.2.1, or example picture pg 67, O-S-Guide.

Separated Earth, more commonly known as a clean earth. Used in Data, Hi-Fi and general IT . The body or/and contaminants are connected to the 'normal' earth. The clean connection is connected to the equipment and would run back to the main earth bar or rod completely separate of any other connections, so as not to pick up any 'noise' or spikes.

 

[mercurystar999]

I only use crabtree sockets and they have twin earth terminals and they are connected. I assumed that they were the same as the sockets for it suites. Used to do lots of office blocks and used MK and they were the same.

 

[Apache]

I only use crabtree sockets and they have twin earth terminals and they are connected. I assumed that they were the same as the sockets for it suites. Used to do lots of office blocks and used MK and they were the same.

"to assume makes an ass of u and me!"

 

[Lurch]

IIRC MK do, or did, 2 versions of the dual earth terminal sockets, 1 with them linked, 1 with them not.