H
holmslaw
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Spark123 said:If it isn't installed in accordance with the MI then it doesn't comply with BS7671, see 134.1.1 (17th ed)
equitum said:...Fair point, and I agree, if the MI state a separate DP switch is required then one must be installed
When carrying out maintenance work on a particular piece of equipment the isolation switch is in your control....without locking off the MCB in a consumer unit situated in another part of the building how can this be in your control?
How do you work on lighting circuits ? How do you work on socket outlet circuits ?
When carrying out maintenance work on a particular piece of equipment the isolation switch is in your control....without locking off the MCB in a consumer unit situated in another part of the building how can this be in your control?
How do you work on lighting circuits ? How do you work on socket outlet circuits ?
Local switching.....
If i want to change a lamp (current using equipment) then isolation by the functional switch is adequate...
If i want to repair the hoover etc then either unpluging it and removing from source is adequate...
In both above instances switching off at MCB for maintenance is overkill.
FACT: BS 7671 does state that effective means, suitably placed for ready operation, shall be provided so that all voltage may be cut off from... all equipment, as may be necessary to prevent or remove danger.FACT: BS7671 does not state or imply that a shower must have a DP isolator installed in the same room, or within easy reach of the shower.
OPINION: The MCB in the CU, or the main switch for the installation, is not an effective means, suitably placed, for ready operation to cut off the voltage to a shower.OPINION: DP pull cord switches are typically installed for convenience of isolation because otherwise the only means of isolation is the main switch in the CU, which would entail isolating the whole installation. Where this is not the case and a separate CU is installed for the shower then the main switch of such a CU is an adequate means of isolation for the shower. This has the advantage of less points of failure, less connections in a high current circuit and fewer electrical accessories in a special location.
No - you can have a rotary/rocker/toggle switch on the wall if you prefer.so bas do you need a pull cord or not
Why does the cord have to be out of reach?If a pull cord dual pole isolator can be installed in the same room, but out of reach of the person using the shower, this is the best solution.
ban-all-sheds said:OPINION: The MCB in the CU, or the main switch for the installation, is not an effective means, suitably placed, for ready operation to cut off the voltage to a shower.
ban-all-sheds said:OPINION: I fail to understand why this debate arises time and time again, given that I have never seen equivalent suggestions that cookers do not need a CCU within 2m of them.
What if you need to isolate it because it is making a fizzing sound, and there's a smell of ozone and melted plastic coming from it, and faint wisps of smoke?Why not. I need to isolate a shower, for maintainance. I go into the room containing the CU and isolate it by turning off the switch.
2m is generally regarded as the maximum distance away that the switch should be and still be suitably placed for ready operation.OPINION:
I have seen several suggestions that the cooker switch does not need to be within 2M of the cooker. Again, where are you getting a distance of " 2meters " from, and why should this be the case ??
When carrying out maintenance work on a particular piece of equipment the isolation switch is in your control....without locking off the MCB in a consumer unit situated in another part of the building how can this be in your control?
How do you work on lighting circuits ? How do you work on socket outlet circuits ?
Local switching.....
If i want to change a lamp (current using equipment) then isolation by the functional switch is adequate...
If i want to repair the hoover etc then either unpluging it and removing from source is adequate...
In both above instances switching off at MCB for maintenance is overkill.
If you wish to change a ceiling rose, then what ?
If you wish to change a socket outlet, then what ?
How can you make first make an argument that a device in the consumer unit cannot be used as a means of isolation, and then not give a valid response as to how you would work on a different circuit without DP switch isolators ? (other thank think of two instances where you use a functional switch, which is not advisable) The answer is you would either have to lock off the device, or ensure it is under supervion, for example lock the doors, have an assistant ensure the device is not turned on, use warning notices etc.
When carrying out maintenance work on a particular piece of equipment the isolation switch is in your control....without locking off the MCB in a consumer unit situated in another part of the building how can this be in your control?
How do you work on lighting circuits ? How do you work on socket outlet circuits ?
Local switching.....
If i want to change a lamp (current using equipment) then isolation by the functional switch is adequate...
If i want to repair the hoover etc then either unpluging it and removing from source is adequate...
In both above instances switching off at MCB for maintenance is overkill.
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