Firefighters across England and Wales have just begun a two hour walkout over proposed reforms to pay and pensions.
The strike will go on until 0800 GMT and specialised auxiliary fire fighters will be drafted in to cover the protesters duties.
Members of the Fire Brigades Union staged a four and a half hour walkout on Friday.
Fire services said they coped well during the strike action.
The dispute, between the Fire Brigades Union and the UK Government, is about changes to pension ages.
More top news
A father-of-two was murdered by three men in a vicious attack as a result of a drugs turf war, a court has heard.
Plaid Cymru kicked off its election campaign today with leader Leanne Wood vowing to defend Wales in Brexit negotiations.
The Tour of Britain is returning to Wales and it is finishing in Cardiff for the first time ever.