Any electricians??
- Thread starter gixer1
- Start date
Chasser
Well-Known Member
The earthing situation needs to be addressed this varied fldeoending on your Distribution Network Operator supply. In terms of mechanical/automatic changeover, I would look at mechanical for domestic installation, as the automatic is only really necessary for time sensitive installations, or sites which parallel with the mains… but that’s a different story!
The installation would require a changeover switch after your meter but before the distribution board. For the generator side of the CO switch it is common to use a 32A male socket and have the 32A female socket on the generator tails. This allows the generator to be stored elsewhere and plugged in when required! You would also require the generator to be protected from an RCD. I would also spend an extra few quid and install a phase failure relay which can be connected to a display light/alarm and will monitor the DNO’s supply voltage to prevent running your generator un-necessarily!
The installation would require a changeover switch after your meter but before the distribution board. For the generator side of the CO switch it is common to use a 32A male socket and have the 32A female socket on the generator tails. This allows the generator to be stored elsewhere and plugged in when required! You would also require the generator to be protected from an RCD. I would also spend an extra few quid and install a phase failure relay which can be connected to a display light/alarm and will monitor the DNO’s supply voltage to prevent running your generator un-necessarily!
As said, the earthing situation is important
Depends whether your house, is wired up on eg. TN-C, TN-S, TN-C_S, or even TT etc. TT being more common in rural areas and places supplied with overhead powerlines, particularly the sort with only two conductors.
A competent transfer switch installer ought to understand that and might even require an earthing rod to be added to make it safer. And for an RCD to work properly. E.g. if, as is most common, your house relies on the protective earth being routed through the neutral of the mains supply to your supplier, that could be interrupted if the line was blown down, or the company was having to work on a fault in an underground cable, leaving your house essentially without an earth connection. In mine for example the water comes in through a plastic pipe, so although the internal plumbing is bonded to the earth point on the electricity supply, that wouldn't help. Without that there are several possible fault conditions that could zap you without tripping an RCD. If you have a power cut due to a fault in the powerline to you, and are feeding your house through a transfer switch, it is quite possible that the house will have no adequate earthing, unless some other arrangement has also been fitted.
The transfer switch must be suitably sized, as it will be in circuit all the time when the mains is working normally. So if e.g. you have a powerful 10 kW electric shower (that takes 45A), and an electric cooker (typically another 32A) using both together could already be taking nearly your full domestic single phase supply, which will probably be no more than 100A. Never mind if you are also running say an electric heater or two, an immersion heater etc. Or night storage heaters. UK house wiring, often relies on "diversity" i.e. the sum total of what your power points could take, if everything was switched on at the same time, could easily exceed what the mains supply is sized for. That's allowed, up to a point, on the assumption that would will probably never actually do that at the same time. Your consumer unit may not trip, nor even the electricity supplier's big fuse, but all that current would still be running through the transfer switch. If say, your house is like mine, a modest one, I have two ring mains (32A each), a 32A cooker point, an additional electric 10 kW shower subsequently fitted (another 45A), the lighting circuit, etc. Never mind those that have also added an electric vehicle charging point as well.
Then there are issues with powering outbuildings hardwired, or generator supplied, even temporary marquees and powering up lighting, PA systems, band equipment from a generator. I've seen some scary cobbled together setups at wedding parties and amateur outdoor concerts for example, but couldn't make a fuss for fear of spoiling the occasions, just some friendly words of advice behind the scenes about simple do-able ways to tighten them up a little.
Some legal advice, from an authoritative website, selective quotes:
All work that involves adding a new circuit to a dwelling, ... will need to be either notified to Building Control with a building regulation application, or carried out by a competent person who is registered with a Part P Self-Certification Scheme.
There are two routes available to applicants to ensure they comply with Part P:-
1. Use an electrician who is registered with a Competent Person's scheme. A building regulations application will not be required for the electrical work. We would strongly encourage the use of electricians/installers who are part of a Competent Person Scheme. The electrician should give you a completed BS 7671 test certificate at the end of the job.
2. Submit a Building Regulation application to XXX District Council prior to commencement of work (fees are payable):
B. Where the work is carried out by an unregistered electrician or is a DIY installation, the person must be able to demonstrate to us that they are competent to carry out the work. It is important that we are contacted before commencement of work and again to arrange an inspection before any cables are covered up. Inspections may be carried out in conjunction with our consultant Electrician, for which charges will be incurred.
Back feeding through a "suicide lead" and simply switching off the mains supply at the circuit breaker, if you remember, is potentially dangerous in so many ways, both to you, and even to the linesmen trying to work on your supply. And if something did go wrong, I would imagine that your insurers would take a dim view.
Portable generators often just float, live and neutral. Though there will probably be an earth bonding point connected to the neutral that, if you understood how to use it, might bond neutral to the chassis and whatever else you connected it to, if you wired up the the plugs the correct way around and. And if the earth conductor in your connecting lead was intact. Surprising how many aren't, even on supposedly respectable campsites. I sometimes come across live and neutral reversed, even no earth at all. As detected with a little plug in tester. TBH letting the generator float may be safer outdoors, when earthing it is not practical. Particularly if you are using double-isolated equipment connected to it. It's what I do with my generator (total plastic outer housing so nothing to conduct. Apart from the exhaust which is also plastic shrouded so you can't easily touch it, for a reason). Supplying the campervan, or power tools, site lights etc. But no way would I power up a marquee with PA, disco, lighting,, or a band with it, without a lot more thought, though I have been asked by some who wanted to borrow it.
I certainly don't want to put you off installing a transfer switch, quite the opposite. And of course get it fitted before you need it, hopefully you never will.
Depends whether your house, is wired up on eg. TN-C, TN-S, TN-C_S, or even TT etc. TT being more common in rural areas and places supplied with overhead powerlines, particularly the sort with only two conductors.
A competent transfer switch installer ought to understand that and might even require an earthing rod to be added to make it safer. And for an RCD to work properly. E.g. if, as is most common, your house relies on the protective earth being routed through the neutral of the mains supply to your supplier, that could be interrupted if the line was blown down, or the company was having to work on a fault in an underground cable, leaving your house essentially without an earth connection. In mine for example the water comes in through a plastic pipe, so although the internal plumbing is bonded to the earth point on the electricity supply, that wouldn't help. Without that there are several possible fault conditions that could zap you without tripping an RCD. If you have a power cut due to a fault in the powerline to you, and are feeding your house through a transfer switch, it is quite possible that the house will have no adequate earthing, unless some other arrangement has also been fitted.
The transfer switch must be suitably sized, as it will be in circuit all the time when the mains is working normally. So if e.g. you have a powerful 10 kW electric shower (that takes 45A), and an electric cooker (typically another 32A) using both together could already be taking nearly your full domestic single phase supply, which will probably be no more than 100A. Never mind if you are also running say an electric heater or two, an immersion heater etc. Or night storage heaters. UK house wiring, often relies on "diversity" i.e. the sum total of what your power points could take, if everything was switched on at the same time, could easily exceed what the mains supply is sized for. That's allowed, up to a point, on the assumption that would will probably never actually do that at the same time. Your consumer unit may not trip, nor even the electricity supplier's big fuse, but all that current would still be running through the transfer switch. If say, your house is like mine, a modest one, I have two ring mains (32A each), a 32A cooker point, an additional electric 10 kW shower subsequently fitted (another 45A), the lighting circuit, etc. Never mind those that have also added an electric vehicle charging point as well.
Then there are issues with powering outbuildings hardwired, or generator supplied, even temporary marquees and powering up lighting, PA systems, band equipment from a generator. I've seen some scary cobbled together setups at wedding parties and amateur outdoor concerts for example, but couldn't make a fuss for fear of spoiling the occasions, just some friendly words of advice behind the scenes about simple do-able ways to tighten them up a little.
Some legal advice, from an authoritative website, selective quotes:
All work that involves adding a new circuit to a dwelling, ... will need to be either notified to Building Control with a building regulation application, or carried out by a competent person who is registered with a Part P Self-Certification Scheme.
There are two routes available to applicants to ensure they comply with Part P:-
1. Use an electrician who is registered with a Competent Person's scheme. A building regulations application will not be required for the electrical work. We would strongly encourage the use of electricians/installers who are part of a Competent Person Scheme. The electrician should give you a completed BS 7671 test certificate at the end of the job.
2. Submit a Building Regulation application to XXX District Council prior to commencement of work (fees are payable):
B. Where the work is carried out by an unregistered electrician or is a DIY installation, the person must be able to demonstrate to us that they are competent to carry out the work. It is important that we are contacted before commencement of work and again to arrange an inspection before any cables are covered up. Inspections may be carried out in conjunction with our consultant Electrician, for which charges will be incurred.
Back feeding through a "suicide lead" and simply switching off the mains supply at the circuit breaker, if you remember, is potentially dangerous in so many ways, both to you, and even to the linesmen trying to work on your supply. And if something did go wrong, I would imagine that your insurers would take a dim view.
Portable generators often just float, live and neutral. Though there will probably be an earth bonding point connected to the neutral that, if you understood how to use it, might bond neutral to the chassis and whatever else you connected it to, if you wired up the the plugs the correct way around and. And if the earth conductor in your connecting lead was intact. Surprising how many aren't, even on supposedly respectable campsites. I sometimes come across live and neutral reversed, even no earth at all. As detected with a little plug in tester. TBH letting the generator float may be safer outdoors, when earthing it is not practical. Particularly if you are using double-isolated equipment connected to it. It's what I do with my generator (total plastic outer housing so nothing to conduct. Apart from the exhaust which is also plastic shrouded so you can't easily touch it, for a reason). Supplying the campervan, or power tools, site lights etc. But no way would I power up a marquee with PA, disco, lighting,, or a band with it, without a lot more thought, though I have been asked by some who wanted to borrow it.
I certainly don't want to put you off installing a transfer switch, quite the opposite. And of course get it fitted before you need it, hopefully you never will.
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