diff --git a/polkadot/runtime/westend/src/genesis_config_presets.rs b/polkadot/runtime/westend/src/genesis_config_presets.rs
index f65c975327e6..b4b3e3427447 100644
--- a/polkadot/runtime/westend/src/genesis_config_presets.rs
+++ b/polkadot/runtime/westend/src/genesis_config_presets.rs
@@ -205,7 +205,7 @@ fn westend_testnet_genesis(
 			invulnerables: BoundedVec::try_from(
 				initial_authorities.iter().map(|x| x.0.clone()).collect::<Vec<_>>()
 			)
-			.expect("Too many invulnerable validators!"),
+			.expect("Too many invulnerable validators: upper limit is MaxInvulnerables from pallet staking config"),
 			force_era: Forcing::NotForcing,
 			slash_reward_fraction: Perbill::from_percent(10),
 		},
@@ -379,7 +379,7 @@ fn westend_staging_testnet_config_genesis() -> serde_json::Value {
 			invulnerables: BoundedVec::try_from(
 				initial_authorities.iter().map(|x| x.0.clone()).collect::<Vec<_>>()
 			)
-			.expect("Too many invulnerable validators!"),
+			.expect("Too many invulnerable validators: upper limit is MaxInvulnerables from pallet staking config"),
 			force_era: Forcing::ForceNone,
 			slash_reward_fraction: Perbill::from_percent(10),
 		},
diff --git a/substrate/bin/node/testing/src/genesis.rs b/substrate/bin/node/testing/src/genesis.rs
index 778b39c9d143..376c2bf343e5 100644
--- a/substrate/bin/node/testing/src/genesis.rs
+++ b/substrate/bin/node/testing/src/genesis.rs
@@ -66,7 +66,7 @@ pub fn config_endowed(extra_endowed: Vec<AccountId>) -> RuntimeGenesisConfig {
 			minimum_validator_count: 0,
 			slash_reward_fraction: Perbill::from_percent(10),
 			invulnerables: BoundedVec::try_from(vec![alice(), bob(), charlie()])
-				.expect("Too many invulnerable validators!"),
+				.expect("Too many invulnerable validators: upper limit is MaxInvulnerables from pallet staking config"),
 			..Default::default()
 		},
 		society: SocietyConfig { pot: 0 },
diff --git a/substrate/frame/staking/src/mock.rs b/substrate/frame/staking/src/mock.rs
index 616aaa0f1ba3..ed90d5584af0 100644
--- a/substrate/frame/staking/src/mock.rs
+++ b/substrate/frame/staking/src/mock.rs
@@ -378,8 +378,8 @@ impl ExtBuilder {
 		self
 	}
 	pub fn invulnerables(mut self, invulnerables: Vec<AccountId>) -> Self {
-		self.invulnerables =
-			BoundedVec::try_from(invulnerables).expect("Too many invulnerable validators!");
+		self.invulnerables = BoundedVec::try_from(invulnerables)
+			.expect("Too many invulnerable validators: upper limit is MaxInvulnerables");
 		self
 	}
 	pub fn session_per_era(self, length: SessionIndex) -> Self {