110 volt 16 amp sockets on a 32 amp ring

[Flanders]

Yes but this set up just has an 110 volt socket at the loading bay door with a 110 volt halogen lamp fiited to the wall on a braket so ths light can swing into tne back of the trailer the flex from the light is the correct length to fit into the socket and so not trailing any ware , all oyhet sites i have been on have a 240volt set up

 

[benji]

The 110v transformer is it 110v-0v or 55v-55v ct

 

[Flanders]

Its 55v -55v

 

[Deleted member 9648]

Its 55v -55v

If it's a centre tapped transformer 55-55v then the mcb's must be double pole,that is a separate coding issue from the lack of O/L protection. Code 2 for the O/L issue and code 2 for S/P mcb's.

 

[Flanders]

Yes sorry to clarify I have coded them separately as code 2 observations , all i was saying was that if they had been double pole 32 amp mcbs and the installation was to a good standard which it wasn't I would off been edging to a code 3 observations due to the use of the installation and no signs of thermal damage , its just the part were there is no OL protection for the individual lights but is this required ?

Can an 500 watt halogen light course an over load for example when the lamp blows and pull more than 16 amps and so possibly coursing damage to the 16 amp socket or to the 1.5mm flex supplying the light . I don't think it would and not sure of the maths if any to work this out

 

[Lucien Nunes]

A lamp is unlikely to cause an overload as it will tend to blow very quickly if much of the filament is shorted out, so in one sense it's a fixed load. But certain types of lamp, especially small powerful halogens, can flash over inside the bulb as the filament breaks and draws an arc. To control the damage the lamp maker will specify a maximum fuse or MCB rating and curve, to limit the let-through in the event of violent lamp failure.

I have been standing next to a Par 64 that had a lamp flashover when protected only by a B32 and it was like a cannon being fired - A singing arc for about 1/2 second followed by a huge flash and bang and broken glass and quartz shot out of the front all over the room. A linear is unlikely to do this because the terminals are so far apart but still I would respect the manufacturers' fuse specs.

 

[UKMeterman]

Hi,
I have seen linears explode as well, very nasty as they were being used for indoor down lighters in a church. There was no intervening glass shield. When they fail the arc causes the pressure pulse causes the quartz tube to burst.

In this particular case it may be the impedance of the 230-110 transformer that has limited the fault current of any arcs that they have had. I would also suggest getting the MFT out and check the prospective fault current is acceptable for a 32A circuit breaker.

 

[Flanders]

The only test of done so far is ring continuify on the live 1.74 , neutral return 1.77 and earth 1.70 , IR of 128 live to live and 127 live to earth , i have not done any live test yet not sure if my mft will test at 110 volts i will have to check , i am going back to the site in a couple of weeks so will do some more investigation then. As these reading are high i think this is another reason to down rate the mcb to 16 amp