Wiring to a boiler

[kdLeeds]

The wiring to my central heating boiler is currently wired in T&E plus a permanent live.

At the moment, the only way to isolate is at the consumer unit.

I have seen a 3 pole isolating switch. Would using one of these sited next to the boiler be a better option.

Ideally I would like to use some sort of plug & socket, at least then you can see that the connection is broken, but i'm not sure if this is advisable. Any suggestions

With thanks

 

[Gasman1015]

Switched fused spur with 3 amp fuse.

 

[plugwash]

normal method is to put a switched fused connection unit in the supply to the complete CH system.

i guess you could use a 3 pole isolator to just isolate the boiler but i'm not sure what the point would be, if the boilers off the rest of the system isn't much use.

 

[kdLeeds]

Wouldn't a normal switched fused spur just break th T&E leaving the permanent live?

The reason i'm looking at this, is to protect the plumber who services the boiler. If an isolator is next to the boiler, then it's convenient for him to switch it as necessary.

Thanks for taking the time to reply.

 

[Adam_151]

You put the fused spur before the switched live bracnhes off, normally in between the supply and the main CH JB

 

[RF Lighting]

You should wire the spur as suggested. If you fit a TP isolator for the boiler then there is a risk that someone could switch of the isolator assuming that it isolates the whole heating installation (as is the normal setup) then work on part of the installation (such as a room stat etc) that would still be live.

 

[Gasman1015]

The wiring center of the heating system is where the fused spur should connect to.
That way all controls and boiler can be isolated at once.

 

[kdLeeds]

At the moment, the heating system is on its own circuit breaker in the consumer unit, so in theory I need do nothing. (apart from wire the permanent live to the same breaker. at the moment it's taken from a joint box on a ring main, so sorting that is a priority)

The reason I was thinking of isolating near to the boiler is because the boiler is in a cellar & the consumer unit is in a utility area and so not that convienient for the plumber.

Thanks again for your help.

 

[RF Lighting]

At the moment, the heating system is on its own circuit breaker in the consumer unit

at the moment it's taken from a joint box on a ring main

Which is it? Is it on its own circuit or fed off the ring?

You will need to provide a spur to feed the boiler as a form of local isolation to the boiler regardless of where it is fed from. Also check the manufactures literature for the boiler as most specify a DP isolator and also the boiler will probably need to be protected by a 3A fuse.

 

[kdLeeds]

It's on its own circuit apart from the permanent live which, at the moment comes from the ring main.

I intend to remove this permanent live feed & take a new one from the heating circuit breaker in the consumer unit. Then it will be completely on its own circuit, and switching off this breaker will isolate the whole system (switched live & permanent live) when the boiler is being serviced.

I just wanted a more conveinient place for a plumber to isolate & that's why in my first post I asked if a triple breaker (live, neutral & per' live) was an acceptable way of doing this

I hope this makes sense, if not, please be patient.

 

[RF Lighting]

Sorry What? Your Heating is fed off two circuits . Who wired it like this? You should have a feed to a switched spur which isolates everything. What does the switched live do? is it from the controller or a room stat?

Get an electrician.
Get it sorted out.

 

[kdLeeds]

The switched live is from the heating controls & the permanent live allows the pump to run on for a while (about 10 minutes) after the boiler has shut down. (the pump is connected to the boiler terminal block)

 

[Spark123]

The permanent live should come from the heating controls as well, nowhere else. Turning off the supply at one point should isolate everything on that circuit. At present you have a borrowed neutral problem which if not sorted can cause someone working on it to be shocked (says voice of experience).

 

[kdLeeds]

Unfortunately the timer & thermostat cables are plastered into the walls and the easy route is from the CU, that's why I was hoping to take the permanent live from there (the same breaker that feeds the timer)

I don't understand the borrowed neutral. T&E comes from the CU (there is no neutral taken from anywhere else)

And wouldn't the 3 pole connection unit I spoke of earlier solve that problem by breaking live, sw live & neutral?

 

[Adam_151]

I don't understand the borrowed neutral. T&E comes from the CU (there is no neutral taken from anywhere else)

There is a live taken from the ringmain, that doesn't return via the neutral of the ringmain, it returns through the neutral of the CH circuit, which isn't good becuase if you isolate and work on the circuit that the neutral is borrowed from if you break the neutral, you can get a whack from the downstream part of it (current flows from live of a different circuit, through a device, and if you cut that neutral and then happen to touch the end that doesn't go back to the CU... you provide a return path to terra firma)

And wouldn't the 3 pole connection unit I spoke of earlier solve that problem by breaking live, sw live & neutral?

On the basis of making gas engineers safe then yes it would, but anyone working on the circuits prior to the isolator is at risk, oh and I hope that live from the ringmain is fused down...