Fire rating of fuseboard

[Calebp43]

I recently came across a video on YouTube and the guy fit a fuseboard. Very tidy job but I was confused as he used couplers to have the board not flush with the wall and there was massive holes in the back where the cable comes through.
1) doesn't it need to be ip rated so nobody can get there hands in?
2) doesn't it need to be fire rated?

Just posting this as I want to know if there is a flaw in my thinking somewhere. Here is the link to the video -

 

[Dustydazzler]

Have seen quite a few YouTube celeb Sparks space off a board from the wall using conduit couplers or a 2 inch off cut of pipe for example. Giving them a nice space to bring all the cables round under the board and in Via the back.
A consumer doesn't need to be Fire Proof / Rated. It needs to be constructed from non-Combustible material e.g Metal.
If it is spaced so far off a the wall that you can reach your fingers underneath and poke your fingers in Via the back then it would fail on IP rating. I believe sides and back must be IP2X. But from a Video its hard to tell how far one can poke your fingers inside.
Much will depend on how skinny your wrist is and how long your fingers are I guess.

 

[telectrix]

"How long do you want your fingers?"

" I'd like to keep them"

 

[Avo Mk8]

Much will depend on how skinny your wrist is and how long your fingers are I guess.

Or preferably this (example)!

https://www.amazon.co.uk/GOWE-IEC61032-IEC60529-Probe-Finger/dp/B01GMGFNIE

 

[richy3333]

Some manufacturers sell stand off brackets for their consumer units

 

[Dustydazzler]

I do like to space a board off the wall a bit for 2 main reasons...

1, it allows you to bring all the cables in from the back and thus keep all the sides intact
2, often garage walls are not straight so by spacing off the wall a bit you avoid having a twisted board

An inch off the wall there is no real someone can get all their fingers into the rear knock-out, not unless they have incredibly long fingers

 

[oscar21]

I've always used 2 vertical 2x1 pieces of wood when doing this, sometimes with a piece of ply across them if I'm feeling generous.

 

[Aaron b]

Wouldn't it be being able to touch live parts with a standard finger and not just accessing the board? Going through the back is usually much simpler in domestics.

I prefer the busbars to have a cover instead of the the barriers like in the fusebox boards, some of the better ones are IP2X with the cover off.

 

[mainline]

I recently came across a video on YouTube and the guy fit a fuseboard. Very tidy job but I was confused as he used couplers to have the board not flush with the wall and there was massive holes in the back where the cable comes through.
1) doesn't it need to be ip rated so nobody can get there hands in?
2) doesn't it need to be fire rated?

Just posting this as I want to know if there is a flaw in my thinking somewhere. Here is the link to the video -

He should have fitted SP+N rcbos as an N to E fault could still trip others.

 

[Aaron b]

He should have fitted SP+N rcbos as an N to E fault could still trip others.

Is this something you have experienced? I don't generally fit DP rcbos. I like that they make ir testing easier but I don't feel it's worth the extra expense.

 

[mainline]

Is this something you have experienced? I don't generally fit DP rcbos. I like that they make ir testing easier but I don't feel it's worth the extra expense.

Yes, I have experienced this many times, twice I recall on outside lights that had water ingression.

 

[Aaron b]

Yes, I have experienced this many times, twice I recall on outside lights that had water ingression.

Any ideas on what would cause that?

 

[DPG]

Any ideas on what would cause that?

Leaky fittings and/or condensation.

 

[Dustydazzler]

Isn't the correct term Single Pole and Switched N. Not DP

 

[mainline]

Any ideas on what would cause that?

Neutral earth faults where you can get circulating currents, particularly on tncs systems

Unless you disconnect the Neutral, the fault is going to remain

 

[timhoward]

Is this something you have experienced? I don't generally fit DP rcbos. I like that they make ir testing easier but I don't feel it's worth the extra expense.

If you consider how long the CU is going to sit there, the extra cost is pretty negligible really. And they don't twist as much (thinking Fusebox)

Consider this scenario:
Lighting circuit has N-E fault as outside light filled up with water.
Cooker circuit with no faults.
Both RCBO's on.

Turn on Cooker, the return current has an extra path via the fault in the lighting. If the N-E resistance is low enough one or both of the RCBO's will trip. So far that is exactly the same whether SPSN or SP RCBOs.

The benefit to the customer of the SPSN is that over the phone I can now diagnose it and as long as the SPSN lighting RBCO is off they can now turn the cooker back on and make their kippers on toast. If we skimp and fit SP RCBO's the faulty N path remains and they have to learn to like spam sandwiches.

One could argue that (specifically) for tolerance of N-E faults a fully loaded SP RCBO board is even worse than a dual RCD board.

 

[mainline]

If you consider how long the CU is going to sit there, the extra cost is pretty negligible really. And they don't twist as much (thinking Fusebox)

Consider this scenario:
Lighting circuit has N-E fault as outside light filled up with water.
Cooker circuit with no faults.
Both RCBO's on.

Turn on Cooker, the return current has an extra path via the fault in the lighting. If the N-E resistance is low enough one or both of the RCBO's will trip. So far that is exactly the same whether SPSN or SP RCBOs.

The benefit to the customer of the SPSN is that over the phone I can now diagnose it and as long as the SPSN lighting RBCO is off they can now turn the cooker back on and make their kippers on toast. If we skimp and fit SP RCBO's the faulty N path remains and they have to learn to like spam sandwiches.

Once could argue that (specifically) for tolerance of N-E faults a fully loaded SP RCBO board is even worse than a dual RCD board.

You could always fit DP mcbs. into a split load CU.

 

[pc1966]

Turn on Cooker, the return current has an extra path via the fault in the lighting. If the N-E resistance is low enough one or both of the RCBO's will trip. So far that is exactly the same whether SPSN or SP RCBOs.

With single/dual RCD yes, but not RCBO unless it has an up-front RCD (as sometimes done for TT systems). For RCBOs to interact in a non-obvious manner it would need to be a N-N sort of fault.

The N-E fault tripping out other circuits happens because of the common RCD to several MCBs in older board. Basically as far as that RCD is concerned they are all the same circuit.

I would always go with DP (SP + N) RCBOs if I could as they make testing easier. But where it really matters is systems with RCDs higher in the supply chain, such as TT with incomer RCD, or a farm with 300mA RCD for fire safety reasons, or sub-main where you can't disconnect in time simply on Zs, etc. Without switching N there you don't have proper selectivity and any N-E fault will trip out the upstream protection.

 

[timhoward]

With single/dual RCD yes, but not RCBO unless it has an up-front RCD (as sometimes done for TT systems). For RCBOs to interact in a non-obvious manner it would need to be a N-N sort of fault.

I agree with you that I was wrong about which device will trip, I wasn't thinking straight. The "large load" RCBO (not shown) will not trip as everything "coming in" is also "going out".
But I think my wider point is correct - this kind of thing can still happen (supply at top, large load with own RCBO on left, another RCBO with faulty circuit on right).
And with a SP+N RCBO the customer can isolate the fault until someone can come and prod it.

 

[happysteve]

Consider this scenario:
Lighting circuit has N-E fault as outside light filled up with water.
Cooker circuit with no faults.
Both RCBO's on.

Turn on Cooker, the return current has an extra path via the fault in the lighting. If the N-E resistance is low enough one or both of the RCBO's will trip. So far that is exactly the same whether SPSN or SP RCBOs.

Eh? I don't understand how this would work...

If you have an upstream (e.g. time-delayed) RCD then sure, you need the RCBO to disconnect the N so that it clears as well as detects the fault. But if there is no upstream RCD, you're fine... surely?

EDIT: just seen your later post, fair enough!