New Consumer Unit and 17th Edition

Could anyone please tell me whether I'm correct in assuming that to fit a new consumer unit this would be classed as a "New Installation" and therefore the current wiring of the property would have to comply fully with the 17th Edition Regs.

The reason I ask is because currently all socket outlets are on one circuit, as is the lighting circuit.

That is upstairs and downstair circuits are each on its own BS 3036 rewireable fuse.

My ultimate question is:
Purely on the fact that seperate circuits do not exist for upstairs and downstairs. Do I need a rewire before I can have a New Consumer unit fitted.

I'm guessing the socket outlets could be separated into 2 circuits (up and down)....same for the lighting but could be tedious. So would a rewire be less messy.


Any advice greatly appreciated.

DaveSz said:

Could anyone please tell me whether I'm correct in assuming that to fit a new consumer unit this would be classed as a "New Installation" and therefore the current wiring of the property would have to comply fully with the 17th Edition Regs

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Yes

The reason I ask is because currently all socket outlets are on one circuit, as is the lighting circuit.

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Not necessarily a problem if it's a 2 up 2 down, small house. Concern would be total cable distance and if the expected load across the ring is likely to be greater that 32A ( or about 7000w)

That is upstairs and downstair circuits are each on its own BS 3036 rewireable fuse.

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If the wiring is old, 25+ years it may well need replacing, IR tests will confirm if the wiring is suitable for new CU and the sensitive nature of RCD / RCBO's

My ultimate question is:
Purely on the fact that separate circuits do not exist for upstairs and downstairs. Do I need a rewire before I can have a New Consumer unit fitted

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Maybe depending on age. Even if the wiring is serviceable your need to consider earth bonding to water and gas main services, large earth MEt to CU, 25 mm tails from mains head to CU

I'm guessing the socket outlets could be separated into 2 circuits (up and down)....same for the lighting but could be tedious. So would a rewire be less messy.

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Post some pictures of the existing wiring around the fuse board, mains head and let's see the site.

Any black cables will be passed sell by date, all cable should have CPC / earth wire. Check at your light switches and see in the cables has a separate conductor to the live / neutral.

A rewire is normally a messy business, an asset to a house- but messy getting it all in and done.

Rewires are made easier if conduit and cable routes are easy access, whereas tiled floors, wooden flooring systems and a home that is clutter make for blood, sweat and (customer) tears.

What other circuit have you?

Kitchen ring
Cooker
Water heater / immersion
Shower
Central heating and controls
Outside shed[/quote]

Chri5 said:

DaveSz said:

Could anyone please tell me whether I'm correct in assuming that to fit a new consumer unit this would be classed as a "New Installation" and therefore the current wiring of the property would have to comply fully with the 17th Edition Regs

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Yes

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Really?

Why? You aren't designing or installing the existing wiring, so it isn't covered by the EIC you write for the CU.

BaS- I like your posts, but sometimes it's easy to understand why (occasionally) you come across as over picky. Fair play when ambiguity might cause doubt, but not every ones syntax / language or way of expressing themselves fits inside your box marked 'perfect English'.


To expand on what BaS is mentioning.

Any installation should be done to the 17th edition, BS7671: 2008

It's not practical to update every component of a site for a CU change out, but the requirements of an IEC will request that components of the site are in keeping within the regs and that all is safe, and serviceable.

When a CU change is done to the 17th, the protection requirements of the 17th will be required.

RCD requirement being 1 element, main bonding, supply tail size, MET to CU size. All cabling being commissioned on to the CU has a requirement to be within tolerance of tests on each circuit, per the 17th schedules.

Insulation resistance, circuit impedance & continuity, earth fault loop impedance tests and RCD trip times are a recordable EIC cert requirement.
If the values are inside the thresholds, then the wiring is acceptable.
Things such as damage, aged cabling, lack of CPC (earth), sheath cracking, pre PVC cable all tend to suggest a rewire will be required.

Site conditions vary, and only a on site assessment will confirm the full extent of the project and hence the cost.

Chri5 said:

BaS- I like your posts, but sometimes it's easy to understand why (occasionally) you come across as over picky. Fair play when ambiguity might cause doubt, but not every ones syntax / language or way of expressing themselves fits inside your box marked 'perfect English'.

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Sorry - I wasn't being picky, but this is an interesting point.

Any installation should be done to the 17th edition, BS7671: 2008

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All of it, or only the regs that are easy to meet?

It's not practical to update every component of a site for a CU change out, but the requirements of an IEC will request that components of the site are in keeping within the regs and that all is safe, and serviceable.

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Which parts of the existing installation have to comply with the current regulations, and come to that, which regulations?

I'm being a bit Devil's Advocate here, but I wonder how much thought people (not you in particular, you just happen to be the one I'm replying to) are putting into this, and on what they are basing their position.

When a CU change is done to the 17th, the protection requirements of the 17th will be required.

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Why? Just because those are easy to do? What makes you pick some regulations to follow and ignore others?

RCD requirement being 1 element, main bonding, supply tail size, MET to CU size. All cabling being commissioned on to the CU has a requirement to be within tolerance of tests on each circuit, per the 17th schedules.

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And what if they aren't OK? Are you saying you can't replace the CU?

Insulation resistance, circuit impedance & continuity, earth fault loop impedance tests and RCD trip times are a recordable EIC cert requirement.

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True, but what about the items on the Schedule of Inspections that you can't actually inspect?

My personal opinion:

1) PIR
2) Rectify defects (if any)
3) Issue satisfactory PIR
4) Carry out consumer unit change
5) Issue EIC for consumer unit change, adding the PIR reference number and a note in the 'comments on existing installation' box.

That should comply with 131.8