This study investigates the volatility connectedness between the Irish and Great Britain electricity markets and how it is driven by changes in energy policy, institutional structures and political ideologies. We assess various aspects of this volatility connectedness including static (unconditional) vs dynamic (conditional), symmetric vs asymmetric characteristics between 2009 and 2018. We find that the volatility connectedness is time-varying and it is significantly affected by important events, policy reforms or market re-designs such as Brexit, oil price slump, an increasing share of renewables, and fluctuations in the exchange rates. Our asymmetric analysis shows that magnitude of the good volatility connectedness is marginally larger than that of the bad volatility connectedness. Our result suggests that good volatility levels would be even higher once the Irish market adopts the carbon price floor. Therefore, supporting renewable generation by setting an appropriate price of carbon in interconnected wholesale electricity markets will improve market integration.