Fault Light on Openreach Fibre to the Premises Box

[pebbleridge13]

Hi,

Our BT fibre Broadband is working fine and a speed test reports 72.8 Mbps download speed.

But we have a fault Light on Openreach Fibre to the Premises Box.

I don't want to phone BT because I'll probably be on the phone for hours turning it off and back on again (which I have already tried).

Should I report it now or leave it until something actually goes wrong.

[licquorice]

Presumably it is just the BBU (Battery Backup Unit) showing faulty. If so you can either just ignore it or bypass the unit altogether and plug the power lead directly into the ONT rather than the BBU.

The BBU is no longer fitted to new installs as it was only there to provide power for FVA (Fibre Voice Access) which is no longer used.

[pebbleridge13]

Thanks for your prompt reply.

I had no idea I had a BBU and an ONT in there, but it is the smaller of the 2 boxes inside the big box (how about that for a technical description.

On inspection I can see that there is a "Charging" Light (not illuminated) alongside the Fault light, so I think your assumption of a faulty BBU is correct.

Just to confirm, it does absolutely nothing useful, doesn't hold data or anything like that and I can safely connect the power directly into the ONT.

What do I do with the cable (that looks a bit like a network cable) that runs between the BBU and the ONT.

Forgot to mention I do have a fibre land line, is that not the same as Fibre Voice Access?

[licquorice · Accepted solution]

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@pebbleridge13 wrote:

Thanks for your prompt reply.

I had no idea I had a BBU and an ONT in there, but it is the smaller of the 2 boxes inside the big box (how about that for a technical description.

On inspection I can see that there is a "Charging" Light (not illuminated) alongside the Fault light, so I think your assumption of a faulty BBU is correct.

Just to confirm, it does absolutely nothing useful, doesn't hold data or anything like that and I can safely connect the power directly into the ONT.

Correct, it is just a backup battery, nothing else.

What do I do with the cable (that looks a bit like a network cable) that runs between the BBU and the ONT.

That's the output power lead, remove it and power the ONT directly from the power brick that currently goes to the BBU input.

Edit: The other lead between ONT and BBU can simply be removed.

Forgot to mention I do have a fibre land line, is that not the same as Fibre Voice Access?

No, FVA was an earlier version of voice provided by Openreach which has now been superseded by Digital Voice from BT.

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[pebbleridge13]

Brilliant,

I'll do exactly what you suggest when I've finished with my PC later today.

Many thanks for your advice.

[pebbleridge13]

Just to let you know that by the time I got around to actually disconnecting the BBU, the fault light had gone out, so I left it connected.

[Starman]

I wonder if it was due to low voltage perhaps initially indicating the cells were faulty now it was plugged in for a few days the voltage in the cells have recovered and cleared the error.

[pebbleridge13]

That might be a good point.

We had a power cut the other day (after the light came back on) it was only an hour or so but when the power came back on, so did the fault light.

A couple of days later and the light is off again.

I suspect the batteries are near the end of their life and are not holding much charge.