advice on garage electrics

[pondy]

i moved into my first house 7 month ago and just got around to sorting the garage electrics out. I already had a supply to the garage, there is an armoured cable that goes I consumer unit with a 30a fuse under the stairs. this cable then goes under my garden into the garage. before it had one socket and 1 strip light and a metal fuse box. I got my dad to change everything, he is not an electrician but a plumber so has general knowledge of electrics from installing boilers etc. me on the other had have no idea so I have tried to show as many pictures of what has been installed. we have installed a new consumer unit, outside security light, 3 strip lights and 6 double sockets and a single socket on a ring main (wire goes to socket then back to the consumer unit??). the problem I have is my two 16a sockets, one is on a 16a type b rcbo and the other is a 16a type c rcbo (consumer unit and all rcbo came second hand on ebay), the sockets just have a single wire going to them, if I plug my portamig into the c socket on the higher settings it will trip the rcbo, if I plug it into the b socket it will trip the box on the right of the consumer uint were the power comes from my house into the unit. an idea whats the problem?

supply from house





new comsumer unit in garage







2 16a sockets

 

[BrokenBiker]

depends on what settings you are using the welder on. what is the top rated input current on the welders info plate? if it says input current is 16 amp then you should be fine, if its higher you will trip the 16 amp when you get to a certain setting, which just means once you have found that setting, ease it back a touch and then never go any higher.

my parweld is rated for 16 amp input but it runs fine on 13 amps for what I use it for most of the time

 

[AndyStobbs]

Perhaps your b curve rcbo is defective as it should trip that before it trips the main incomer, as it is with the c curve.

 

[madkayaker]

I doubt that the mob will be faulty it's fairly rare. Mcb can be difficult to set up discrimination properly. Recently had an issue where each rack in a server bay was 16A b then feed by 32A c with section protection of 63D. A fault in one computer took whole lot out! (Government customer not happy)

 

[Robotstar5]

No one picked up BS951 clamp on armour? should use a proper gland.

BS 951 1999 states in note 3 to its scope that such clamps are not intended for connection to the armour or sheath of a cable

 

[madkayaker]

Missed that thought that was the board that was changed

 

[Robotstar5]

Missed that thought that was the board that was changed

No, that's the house end, no discrimination either, 3 RCBO/RCDs in series

 

[brightspark]

loose the double pole rcd on the incoming mains to your new db in the garage its serving no purpose as u are using rccbo s on all the output circuits and see where u go from there . the rcbos will be 30ma and if the incoming rcd is 30ma it will trip if any one of the rcbo s trip as well killing all circuits . and as another poster stated earth clamps arent suitable on the wire sheath only glands with earth tags giving a good mechanical conection

 

[BrokenBiker]

I didn't pick up on the sheath clamp either, thought it was before the new board.

 

[BrokenBiker]

also didn't fully read the description about the tripping fault, as said above really, with rcbo's on every output the RCD is pointless, that may as well just be a suitably rated main switch.

I assumed you were just asking if your portamig would run off the 16 am supplies, didn't read about the b curve tripping the rcd too

 

[wheresmejumper]

if there isnt enough slack on the SWA to reach the base of the CU with a gland,
re-strip some more of the sheath and put a good few of the outer strands into a connector.then bring an earth from the connector into the CU.
Its not ideal but would be electrically sound

 

[madkayaker]

put a proper gland on the SWA and if there isn't enough length or anywhere to land to use an adaptable box under the CU

 

[wheresmejumper]

that would be better again

 

[pondy]

Hi guys, bringing up an old thread.
The first two pictured are the house Id, i have not touched anything here, we installed everthing else apart from the rcd on the incoming Mains in the garage.

Another thing I did not mention is the armoured cable is 4 core but only 2 wires are used, the other 2 are not connected and sitting in the grey box at the end of the armoured cable in one of the pictures, I have not looked at the connections at the house end. Was thinking I could connect the other two wires in?

The earth in the garage comes out of the consumer unit into the back car park and under ground, I suspect it has a spike driven into the ground?


Right if I loose the rcd in the garage and sort the earth I will be able to use my 16a plugs without tripping? Could Someone please post links of suitible earth connection and adaptor box to go in place of the rcd.

 

[madkayaker]

You need to sort the earthing at the house end. You need a SWA glad with an adaptable metal box all earthed down. You need to have RCD protection if it's still tripping after you have sorted the earth you have bigger problems

 

[pondy]

Ok just someone else said loose it as it serving no.purpose. As im using rcbo on all circuits.

So have a metal box on the wall with the cable going through it, swa gland clamping cable to box then earth cable connected to box into the cunsumer unit?

 

[brightspark]

i

Ok just someone else said loose it as it serving no.purpose. As im using rcbo on all circuits.

So have a metal box on the wall with the cable going through it, swa gland clamping cable to box then earth cable connected to box into the cunsumer unit?

correct .just bypass it it serves no purpose as u have rccbo on all circuits .just make sure both ends have glands fitted on metal adaptable boxes using the earth tags on glands and a bit of 10mm mm earthwire conected in to db at both ends

 

[Robotstar5]

Found an easy to follow guide to SWA gland fitting here

 

[brightspark]

Found an easy to follow guide to SWA gland fitting here

easy to follow with pictures. if the cable is long enough u can carry the cores through the metal box with a grommet fitted on the outlet direct in to the db as long as u leave the inner insulation over the cores .eg double insulated it saves joining the cables in the box with conectors

 

[pondy]

I will not have enough lengh on the armoured cable to reach the consumer unit if I removed the large switch next to consumer, if I fit a metal box and gland then fit another box inplace of the switch to joint wires from consumer to armoured cable? when fitting metal box in garage I run earth from this to consumer? Do I leave the earth that goes from consumer out into carpark?