A 300 year old cathedral Notre Dame in Paris burns to the ground, is it the renovations or something else?

Workers on the roof started the fire and it got out of control in the centuries old wood.

It's a lot older than 300 years. Most of the stone structure is still standing, so it hasn't burned to the ground. It's believed to have been some kind of electrical fault that caused it.

The cause has not yet been determined. All construction sites are fire hazards. OIly rags can actually self-combust and many large fires have been caused by this, The Normandie, the famous French ocean liner, was destroyed by a fire during renovations, by a welding torch.

Although there was extensive damage, the famous Rose Windows were saved, the have was intact, and much of the original building is still intact.

Parallels have been drawn between the Notre Dame fire and the 1984 fire which partly destroyed the York Minster in London. As in the case of the York Minster, Notre Dame will survive.

1 - it's not burnt to the ground

2 - they haven't determined this yet

It hasn't burned 'to the ground'. Much of it is still standing - mostly the stone parts.

It's more like 800 years old, most of the area that was destroyed is wood and wood burns. It looks like something electrical being used for the renovations may have caused it, but we may never know.

The insides are WOOD. NO ONE knows exactly the cause.

It would be expected that a construction workers torch or welding things could start a fire..

they can smoulder behind stuff for long time before flames are visible

ONLY 300 years old. Parts of it are much older. The cathedral was begun in 1160 and largely completed by 1260

No fire suppression system, it was just a matter of time.