I recently did some work a plugged in portacom which looked like it has had the switchboard replaced in the past year.
I noticed that the A/C circuit was not on the RCD, it was my understanding that all subcircuits in the portacom have to be on a RCD and that the hardwired exception in 3000 doesnt comply but Im wondering if I have missed something?
I was also impressed to find 2 other portacoms on the same site plugged in with 16amp leads and brand new test tags with 63amp main switches and multiple circuit breakers so after a quick chat to the client this was changed.
Portacom A/C
Re: Portacom A/C
Yes, if it is plugged in, and comes under 3001, then all final subcircuits must be RCD protected.
Along with the current limiting required to match the supply lead rating, the "switchboard" can be as simple as just one 16A RCBO to protect all FSCs in the transportable.
Along with the current limiting required to match the supply lead rating, the "switchboard" can be as simple as just one 16A RCBO to protect all FSCs in the transportable.
Re: Portacom A/C
You are correct that current requirements for connectable installations - which includes plug-in portacoms - require RCD protection for all final subcircuits.
For the apparent mis-match between possible load and rating of supply fittings, not enough info to tell whether this was an issue or not.
It's OK to have more than 16 A load, as long as there's limitation of current to the lowest-rated supply lead fitting - in this case, 16 A.
This curren-limiting rule doesn't apply to old caravans with N-E link; but there are no portacoms that old - back then they were all hard-wired to installation rules.
What's not OK is to have "test tags" on any portacom. As connectable installations they are required to have a WoEF issued by an inspector.
Anyone allowing them to be plugged into supply without a WoEF is breaking the law [ESR 76]
For the apparent mis-match between possible load and rating of supply fittings, not enough info to tell whether this was an issue or not.
It's OK to have more than 16 A load, as long as there's limitation of current to the lowest-rated supply lead fitting - in this case, 16 A.
This curren-limiting rule doesn't apply to old caravans with N-E link; but there are no portacoms that old - back then they were all hard-wired to installation rules.
What's not OK is to have "test tags" on any portacom. As connectable installations they are required to have a WoEF issued by an inspector.
Anyone allowing them to be plugged into supply without a WoEF is breaking the law [ESR 76]
Re: Portacom A/C
Thanks for that guys, I changed the circuit over onto RCD while I was there, but it never hurts to check to see if I missed something.
As for the overcurrent the hardwired lead had a 15 amp plug on it, plugged into the site lifeguard, in the portacom switchboard there was a 63amp main switch, 1 x 40amp RCD, 1 x 6 amp MCB for lights, and 3 x 16 amp MCB for the power circuits.
I can only assume that since the site lifeguard outlet was protected by a 20amp MCB the sparkies that wired the lead up to it assumed that it would be enough for the overcurrent protection however you never know what the next site setup will be.
As for the overcurrent the hardwired lead had a 15 amp plug on it, plugged into the site lifeguard, in the portacom switchboard there was a 63amp main switch, 1 x 40amp RCD, 1 x 6 amp MCB for lights, and 3 x 16 amp MCB for the power circuits.
I can only assume that since the site lifeguard outlet was protected by a 20amp MCB the sparkies that wired the lead up to it assumed that it would be enough for the overcurrent protection however you never know what the next site setup will be.
Re: Portacom A/C
For the max demand limitation; it's OK to use 16 A device to protect 15 A fitting (eg your plug). But 20 A would not be OK.
And yes, if supplied via a compliant system as per Part 1, the socket will have adequate protection - but that's not part of the CI, and as you say the next site (given a 4-year validity for a WoEF) may well be different.
Curious fact is that if a construction site has 2 or more facilities for connecting CIs, it meets the definition of being a "caravan park" in ESR 4.
And therefore the sockets that site huts plug into must have overcurrent protection at no greater than the rating of the socket, in order to comply with '3001' as required by ESR 60.
Most circuits on construction sites would not meet this requirement, because they only have to comply with '3000'; and even if installed to '3012' can still have subcircuit protection > socket rating.
I suspect even most Inspectors would not be aware of this. Also seems very few construction sites get the required [ESR 75] 6-monthly periodic Assessment by an inspector.
So on a construction site it will be pure luck if the site has overcurrent protection suitable to protect the supply lead fittings for the site huts.
And yes, if supplied via a compliant system as per Part 1, the socket will have adequate protection - but that's not part of the CI, and as you say the next site (given a 4-year validity for a WoEF) may well be different.
Curious fact is that if a construction site has 2 or more facilities for connecting CIs, it meets the definition of being a "caravan park" in ESR 4.
And therefore the sockets that site huts plug into must have overcurrent protection at no greater than the rating of the socket, in order to comply with '3001' as required by ESR 60.
Most circuits on construction sites would not meet this requirement, because they only have to comply with '3000'; and even if installed to '3012' can still have subcircuit protection > socket rating.
I suspect even most Inspectors would not be aware of this. Also seems very few construction sites get the required [ESR 75] 6-monthly periodic Assessment by an inspector.
So on a construction site it will be pure luck if the site has overcurrent protection suitable to protect the supply lead fittings for the site huts.
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Re: Portacom A/C
Very interesting thank you AlexK, I never thought of the site technically being a caravan park